News

The Process Rotary drilling rigs utilise high levels of torque and rotation, with a drill bit at the end of the drill pipe rapidly rotating (between 50 and 120rpm) and boring through the rock formation. The drill bit tends to come in two primary forms: firstly, roller-cone bits, and secondly, fixed cutter bits. Both drill bits see similarly high levels of use within the drilling industry. Fixed cutter bits are also commonly referred to as PDC bits (polycrystalline diamond compact bits – though there are other common types of fixed cutter bits, PDC are amongst the most prevalent). The high frequency and speed of rotations make this form of drilling an effective means of carving through both hard and soft rock formations, alike. This form of drilling uses either air or drilling fluids to clear out the borehole, cool the drill bit and generally reduce friction on the bit, so that it can continue to run optimally. What Rock Formations Does Rotary Drilling Rigs Suit? This form of drilling can be used in a broad range of geological formations, deeper boreholes suit rotary drilling using air, whilst `mud` rotary lends itself to unconsolidated, less stable formations (these include sand and gravel formations); mud rotary is where an additive is added to the drilling fluid which subsequently coats the borehole`s sides to help keep it supported. This drilling method can drill down to depths of thousands of metres, and is often used in a mining or quarrying setting, however it is just as useful in more conventional geotechnical settings, as well. Rotary drilling, for instance, can be configured so as to provide a high quality of core recovery for analysis. Benefits And Limitations Benefits As with any type of drilling, Rotary Drilling Rigs has its positives and its drawbacks. Some of its benefits include: Rotary drilling is fast. In fact, it`s several times quicker than other conventional drilling methods. At the same time, it manages to deliver high-integrity results as it does so. Rig flexibility. These rigs are a geotechnical company`s dream; their ease of setup (and subsequent dismount) make them easy to transport and use all over the country, wherever they`re needed. It`s incredibly dependable. This is a tried and tested means of drilling, that has been refined over time. Drilling companies such as Borehole Solutions have now got it down to a fine tee! Limitations By the same token, however, rotary isn`t perfect. Or rather, no one form of rotary drilling is perfect. As we`ve established, there are several kinds of rotary drilling like air and mud; there are also other options, such as dual rotary and reverse circulation. In other words, whilst one form of rotary may not be right for one situation, it`s more than likely that a different form of rotary drilling could complete the job to a high standard. For example, if cross-contamination is an issue from drilling fluids or mud, then air rotary solves that issue. Likewise, if you`re worried about the borehole`s integrity, then mud rotary is the solution. In this way, then, we see that rotary drilling is an immensely versatile drilling methodology.

It`s not surprising that water well drilling is an ancient undertaking. About 8,000 years ago, the first water wells were hand dug to supply a safe, clean and reliable water source for the earliest civilizations. Our need for water has not changed, but well drilling technology has come a long way since then. In some areas of the world, manually digging a water well is still the cheapest and most practical way to improve water accessibility, especially for one-off wells. However, for contractors and groups looking to add or expand their water well drilling capabilities long term,mechanical drilling can offer a faster, more efficient option. There are two things to keep in mind when choosing water well drilling equipment: 1) The method must match the geology. 2) Consider the costs, both short term and long term. For a single well, manual techniques might not cost much, but can hand drilling methods handle soil conditions on your site? And how does the overall cost play out for digging multiple wells? On the other hand, mechanical well drilling options might be able to complete the job quickly but might not fit within the budget for an operation that is only looking at a few wells annually. Let`s take a closer look at the pros and cons of some popular manual and mechanical drilling techniques to determine which might be the best option for your operation. Manual Techniques For many, digging a water well brings to mind an individual in a deep, muddy hole, passing up buckets of earth, and with good reason. Hand-digging is probably the oldest and most frequently used manual method for gaining access to ground water and it`s a labor-intensive, dirty job. Like other manual techniques – including sludging, manual percussion drilling, drive point and hand auguring – hand-digging requires only simple tools and a lot of hard work, which is why individuals and communities have been using these techniques effectively for so long. As the saying goes, [if it`s not broke, don`t fix it." And for areas with limited access to heavy equipment or fuel, these techniques are still a viable option. Pros: Requires simple tools that are locally accessible Can reach depths of 230 feet (70 meters) or deeper depending on method and geology Work can be completed quickly with large crews Cons: High risk of surface contamination Difficult or impossible to drill through rock or dense soil Most methods become unstable at less than 33 feet (10 meters) Most methods require a high water table Perhaps the biggest drawback to manually digging water wells is how inefficient the process is for multiple wells. Installing up to half a dozen wells in a single area might not break the bank, but repeatedly hiring large crews can add up quickly. Additionally, the geological impediments and the risk of contamination with manual techniques make them less attractive to contractors and groups looking to produce sustainable wells in multiple regions. After considering the pros and cons, if manual drilling appears to be the best option for your project, manual percussion drilling is probably the most effective and widely used technique. The process consists of repeatedly dropping a heavy drill bit connected to a rope or cable in a hole partially filled with water to loosen soil and chip off pieces of rock. A sharpened drill bit and one-way valve at the bottom of the drill pipe can be added to create a hybrid percussion-sludging technique for increased efficiency. Manual percussion drilling is faster than other manual methods, capable of penetrating rock (very slowly) and is easily sealed to prevent contamination. However, mechanical percussion drilling - which mechanized the manual down-the-hole method - is a much more efficient option for operations looking for a long-term solution. Mechanical Methods Where manual drilling methods rely on simple tools, large work crews, hard work and patience to get the job done, mechanical drilling methods use motors, gears and fuel to power through rock and tough soils. These techniques can dig faster and deeper than manual methods and are ideal for contractors and groups looking for efficient, highly maneuverable easy-to-use equipment. For drilling a single well, they might not be cost efficient, but for operations looking to add water well drilling to their services, investing in the right water well drilling rig for your operation can offer fast ROI and open up new possibilities. There are several popular methods, each with its own pros and cons, so consider your needs and the geology of your area of operation before committing to a mechanical drill rig. Jetting: With this method, a pump forces water down a drill pipe and out a narrow nozzle to make a jet of water that loosens the sediment. Water outside the drill pipe carries cuttings up to the surface and into a settling pit, dug next to the borehole. The pump then returns the water back down the pipe. The drill pipe is suspended from a tripod and rotated by hand to keep the hole straight. In fine sand, this method can reach depths of 197 feet (60 meters). Pros: Only requires two people Only tools are pump that can generate sufficient pressure and pipe Cons: Only works in soft, fine-grained sediments Difficult to install sanitary seal to protect from surface contamination Cable Tool: This is a mechanized version of manual percussion drilling. A heavy drill bit is attached to a steel cable and raised and dropped down the borehole. Cuttings are still manually removed with a bailer and several meters of water must be maintained in the borehole to keep the cuttings suspended. Equipment ranges from a basic skid-mounted winch with a tripod to a complex set of pulleys and drums with a large mast. Large cable tool rigs are mounted on a trailer or the bed of a truck and use hydraulic motors to raise and lower the mast and rotate the drums of the cable. These larger units are capable of drilling hundreds of feet deep through virtually any geological conditions. Pros: Uses least amount of fuel Cons: Slowest mechanical method Steel casing required to keep hole from collapsing when working in loose sediment Can require extra equipment like arc welder and cutting torch for drive casing Mud Rotary: The basic concept behind the mud rotary drill rig is similar to jetting. Add a large cutting bit, lengths of steel drill pipe with threaded joints, a motor to turn and lift the drill pipe and a sturdy mast to support the pipe and you are ready for rotary well drilling. Mud rotary drilling also mixes bentonite clay or other materials in the jetting water to improve its ability to lift cuttings. This fluid is called [drilling mud"" and is the [mud" referenced in the method`s name. The two basic categories of mud rotary drilling are: table drive, where a rotating mechanism near the base of the rig turns the drill pipe, and top-head drive, where a motor attached to the upper end of the pipe turns it. In both cases, the upper end of the pipe is attached to a lifting mechanism that moves it along the mast. Both types of mud rotary rigs also have a swivel attached to the upper end of the pipe, allowing drilling mud to be pumped down the pipe while it is rotating. Depending on size, a mud rotary rig can drill up to 3,281 feet (1,000 meters). The LS100 and LS200 drill rigs are mud rotary rigs at the small end of drill rig sizes, but even these smaller machines can drill an 8-inch (20-centimeter) borehole to a depth of 197 feet (60 meters). For more power in challenging soils, Lone Star developed the Hydraulic Series. The LS300H+ is capable of drilling a 6-inch (15-centimeter) borehole up to 300 feet (91.4 meters). Pros: Drilling mud keeps borehole open eliminating need for drive casings Faster than cable tool and jetting methods Cons: Drilling through rock only possible with larger rigs Multiple motors consume more fuel per hour than cable tool rig Large rigs require support vehicles to haul water and drill pipe Air Rotary: The mechanical elements of an air rotary drill rig are similar to a mud rotary rig, including an option of table drive or top-head drive for rotating pipe. The principal difference is the use of compressed air to remove cuttings rather than drilling mud. The air rotary rig uses the same type of drill bits as the mud rig, but it can also drill with a down-the-hole hammer. It uses compressed air to break up rock and can drill very fast. A large air rotary rig can drill more than 1640 feet (500 meters) in the right geological conditions. Pros: Fastest drilling method Quicker setup than other methods Cons: Most expensive method Consumes the most fuel per hour Requires support vehicles and large air compressor

Heading machine body An important part of the roadheader. The body part is located in the middle of the body and is a box-shaped structure welded with high-strength thick steel plate as the main material. The pump station with hydraulic system is installed on the right side of the body, and the control console is installed on the left side. The front upper rotary table is equipped with a cutting part, the lower part is equipped with a blade part, the middle part is equipped with a first conveyor, the lower part of its left and right sides is equipped with a walking part, and the rear part is equipped with a rear support part. purpose It is driven by two hydraulic motors respectively, and the traveling is realized through reducer, drive sprocket and track. component Rotary table, rotary cylinder, body frame and cover plate Shovel part of roadheader An important part of the roadheader. purpose Cut straight underground tunnels. component The shovel plate part is composed of shovel plate body, side shovel plate, shovel plate drive device, driven wheel device, etc. The starwheel is directly driven by two low-speed and high-torque hydraulic motors to collect the cut materials into the first conveyor. Safe operation process Blade operation (1) Lifting and lowering of the shovel plate: if the handle is pushed forward, the shovel plate is lifted up, and the height of the shovel tip from the ground can reach 380 mm; Pull the handle backward, the shovel plate will fall down and connect with the bottom plate, and the shovel plate can lie down for 200 mm. be careful: A. When cutting, the shovel tip shall be crimped with the bottom plate to prevent the vibration of the machine body; B. When the shovel tip is lifted and the cutting head is at the lowest position to connect with the bottom plate, the star wheel collides with the lower part of the cutting head, which will bring adverse effects to the roadheader; C. When walking, the shovel plate must be lifted. (2) Star wheel operation: it is divided into left and right control handles, which operate in the same way. Push the handle outward and the star wheel reverses; Pull the handle inward, and the star wheel turns forward; When the handle is in the middle position, the star wheel stops.

The boom of truck crane is the most important part of crane. The crane uses the pulley block at the top of the boom to support the winch wire rope to suspend heavy objects, and changes the lifting height and working radius according to the length and Angle of the boom. Although the role of the boom is to suspend and transport objects, different boom structures and technologies make the performance and efficiency of the crane is very different. 1. Truck crane boom structure The boom of the truck crane generally includes the main arm and the auxiliary arm. There are two types of truck crane main boom, one is the truss structure boom welded by profiles and pipes, and the other is the box structure boom of various sections. With the development of truck crane, the main boom of truck crane is mostly box structure, and only a few are truss structure. The role of the forearm of the truck crane is to connect the forearm at the end of the forearm when the height of the forearm cannot meet the requirements, so as to lift the object higher. Spinnaker can only lift light objects. Generally, there is only one boom, and there are more than two folding booms or telescopic booms, among which folding truss booms are the most common. 2, truck crane boom telescopic principle (1) The telescopic form of the crane boom is as follows: 1. Sequential telescopic mechanism -- each telescopic arm expands and expands in a certain order. 2. Synchronous telescopic mechanism -- the telescope relative speed of each telescopic arm is the same. 3. Independent telescopic mechanism -- each boom can be independently telescopic mechanism. 4. Combined telescopic mechanism - When the telescopic boom is more than three sections, any two of the above listed telescopic methods can be used for the telescopic mechanism at the same time. (2) According to the technology of the telescopic mechanism, the truck crane can be divided into no pin hydraulic telescopic mechanism and automatic telescopic mechanism. 1. The advantage of needle-free hydraulic telescopic mechanism is that the arm length is convenient to change, the working arm length is many kinds, and the practicability is strong. The disadvantage is that the self weight has great influence on the stability of the whole machine. No pin full hydraulic telescopic mechanism has different combination forms, can be multiple hydraulic cylinder and a row of rope, can also be a single hydraulic cylinder or multiple hydraulic cylinder and two rows of rope. The characteristic of multi-hydraulic cylinder plus rope row is that the last telescopic arm is retracted by wire rope, and the other telescopic arm is directly retracted by the cylinder by multistage cylinder or multiple single stage cylinder or multistage cylinder or single stage cylinder liner. As a result, the section of the last telescopic arm varies more, while that of the other arm segments varies less. 2. Automatic pin expansion mechanism adopts single cylinder, interlocking cylinder pin and arm pin, using precision length measuring electronic technology. Its advantages are light weight, small influence on the stability of the whole machine, fast expansion speed, small changes in the section of the boom, good lifting stiffness, but the technical difficulty, high cost, the length of the boom is less. (From the inside out sequence) Automatic pin type expansion mechanism has interlocking cylinder pin and arm pin, cylinder pin is designed on both sides of the boom, the arm pin is designed on the boom plane. Its advantages are simple structure, strong self-locking, the disadvantage is that the large deformation arm pin is difficult to pull out, need to be stretched back and forth to pull out. After understanding the boom structure and telescopic principle of the truck crane, you can understand the key points of the performance of the truck crane. At the time of purchase, you can choose your own car crane products according to your specific work needs.

Welding is the process of combining atoms (molecules) of two separated objects to form a whole with the help of energy. The welding method can not only connect metal materials, such as steel, aluminum, copper, titanium, etc; It can also connect nonmetals, such as plastics and ceramics; It can even solve the connection between metal and nonmetal, which is collectively referred to as engineering welding. The structure made by welding method is called welding structure, also called engineering welding structure. According to the object and purpose, it can be roughly divided into four types: building welding structure, tank and container welding structure, pipeline welding structure, and conductive welding structure. The so-called building steel structure includes these four types of welding structures. The selected structural material is steel, and most of them are ordinary carbon steel and low alloy structural steel. The main welding methods include manual arc welding, gas shielded welding, self-shielded arc welding, submerged arc welding, stud welding, spot welding, etc. (1) Manual arc welding The method of welding relying on the heat of the arc is called electric arc welding. Manual electric arc welding is a kind of electric arc welding with manual operating electrode, which is the most commonly used method in the welding of building steel structures. The principle of manual arc welding is shown in Figure 7-1. The welding rod and weldment are two electrodes that produce an arc. The arc generates a lot of heat to melt the welding rod and weldment. The end of the electrode is melted to form a droplet, which is transferred to the base metal of the melted weldment and fused to form a molten pool and undergo a series of complex physical-metallurgical reactions. As the arc moves, the liquid molten pool gradually cools and crystallizes to form a weld. Under the action of high temperature, the coating on the steel core of the welding rod is melted into molten slag, which is covered on the surface of the molten pool metal. It can not only protect the high-temperature molten pool metal from chemical reaction with harmful oxygen and nitrogen in the air, but also participate in the chemical reaction of the molten pool and penetrate into the alloy, and form a protective slag shell on the cooled and solidified metal surface. (2) Gas shielded arc welding It is also called gas arc welding. The welding wire and the weldment are used as the two poles. Arc heat is generated between the two poles to melt the welding wire and the base metal of the weldment. At the same time, the shielding gas is sent to the welding area to separate the arc, the molten welding wire, the molten pool and the nearby base metal from the surrounding air. The welding wire is automatically sent in. It is continuously melted under the action of the arc and fused with the molten base metal to form the weld metal. Its principle is shown in Figure 7-2. This welding method, called GMAW (Gas Metal Arc Welding) for short, can also be divided into CO2 gas shielded arc welding due to the different shielding gases. It is the most widely used welding method at present, characterized by the use of large current and fine welding wire, the welding speed is fast, the penetration is large, and the operation efficiency is high. (3) Self-shielded arc welding Self-shielded arc welding was once called gas-free arc welding. Compared with gas shielded arc welding, it has good wind resistance. When the wind speed reaches 10 m/s, it can still obtain a weld with no pores and excellent mechanical properties. Due to automatic welding, the welding efficiency is extremely high. The welding gun is light and does not use gas cylinders, so the operation is very convenient, but the price of welding wire is higher than that of CO2 shielded welding. (4) Submerged arc welding Submerged arc welding is a kind of arc welding in which the arc burns under the cover of fusible granular flux. The bare welding wire continuously fed into the molten pool is both a metal electrode and a filler material. The arc burns under the flux layer, melting the welding wire and base metal to form a molten pool. The molten flux becomes molten slag, which covers the surface of the molten metal pool and separates the high-temperature molten pool metal from the air. In addition to protecting the molten slag formed by the flux, it also participates in the metallurgical reaction with the molten metal, thus affecting the chemical composition of the weld metal. (5) Narrow gap welding This method uses the existing special technology of gas shielded welding. The groove section area of welded joints is smaller than that of manual arc welding or gas shielded welding, which is the characteristic of this method. Narrow gap welding can be carried out at the position of flat welding, horizontal welding and vertical welding. The horizontal welding is suitable for the column joints on the project site. The flat welding and vertical welding are respectively suitable for the corner joints of box columns and the welding of columns and beams in the factory. (6) Stud welding Stud welding is a method of applying welding current between the stud and the base metal to make the local contact heating and jointing. It is mainly used for the welding of shear connectors and concrete anchor bolts. In addition, it is also widely used for the installation of connectors with heat insulation and sound insulation materials. (7) Spot welding First of all, the spot welding here is different from the spot welding in the assembly of building steel structure components. It is a method of resistance welding, which directly energizes the welding area, uses its resistance heating to locally increase the temperature of the welded part, and joins under pressure. Spot welding is commonly used in automobile industry and household appliances, and it is also used for complex joints in steel structures.

1. The stress and structural welds of structural members in the steel structure can be butt welds, fillet welds, combination welds of butt and fillet welds, plug welds and slot welds. The butt welds of important connections or with equal strength requirements should be penetration welds, and the partial penetration welds can be used for thicker plates or without penetration. 2. The groove form of butt weld should be selected according to the plate thickness and construction conditions according to the current national standard Code for Welding of Steel Structures GB 50661. 3. When materials with different thickness and width are butt jointed, a smooth transition shall be made, and the slope value at the joint shall not be greater than 1:2.5 4. When bearing dynamic load, plug welding, slot welding, fillet welding and butt welding shall meet the following requirements: (1) When plug welding and slot welding are used for components bearing dynamic load without fatigue calculation, the distance between the edge of the hole or slot and the edge of the component in the direction perpendicular to the stress shall not be less than 5 times of the thickness of the component, and shall not be less than 2 times of the width of the hole or slot; The length of the longitudinal fillet weld of the overlapping connection at the end of the component shall not be less than the vertical spacing a between the welds on both sides, and the spacing a shall not be greater than 16 times the thickness t of the thinner part without plug welding, slot welding and other measures. (2) Fillet weld with leg size less than 5mm shall not be used; (3) Intermittent groove welds and intermittent fillet welds are strictly prohibited; (4) Fillet weld shall be used to strengthen the combination weld of butt and fillet weld and the full penetration groove weld of T-shaped connection. The size of the strengthened weld leg shall not be greater than 1/2 of the thickness of the thinner part of the connection part, but the maximum value shall not exceed 10mm; (5) For the connection subject to dynamic load and fatigue check, when the tensile stress is perpendicular to the weld axis, partial penetration butt weld is strictly prohibited; (6) Except for the transverse welding position, L-shaped and J-shaped grooves should not be used; (7) When butt joints with different plate thicknesses bear dynamic load, they shall be made into smooth transition. 5. The size of fillet weld shall meet the following requirements: (1) The minimum calculated length of fillet weld shall be 8 times of its weld leg size hf, and shall not be less than 40mm; The calculated length of the weld shall be the length of the weld after deducting the length of arc striking and arc stopping; (2) The minimum length of intermittent fillet weld segment shall not be less than the minimum calculated length; (3) The minimum leg size of fillet weld should be taken as per Table 2, and the leg size of fillet weld should not be less than 5mm under dynamic load; (4) When the thickness of the thinner plate in the welded member is not less than 25mm, the fillet weld with the opening groove should be used; (5) Fillet weld shall be used for welding connection, and thick plate shall not be welded to thin plate. 6. The size and arrangement of fillet weld of lap joint shall meet the following requirements: (1) For the parts that transmit axial force, the minimum lap length of the lap connection shall be 5 times the thickness of the thinner part, and shall not be less than 25mm (the smaller of t1 and t2 is taken for t in Figure 2; hf is the size of the weld leg, according to the design requirements), and the longitudinal or transverse double fillet weld shall be welded; (2) When only longitudinal fillet weld is used to connect the end of the profile steel member, the width of the profile steel member shall not be greater than 200mm. When the width is greater than 200mm, transverse fillet weld or intermediate plug weld shall be added; The length of the longitudinal fillet weld on each side of the profile steel member shall not be less than the width of the profile steel member; (3) When lap welding is adopted for lap connection of section steel members, continuous welding shall be carried out at the corners. When the lap fillet weld at the end of the rod is welded around, the length of the weld around should not be less than 2 times the size of the weld leg, and should be welded continuously; (4) The maximum leg size of the lap weld along the edge of the base metal shall be the thickness of the base metal when the plate thickness is not more than 6mm, and the thickness of the base metal minus 1mm~2mm when the plate thickness is more than 6mm; (5) For the casing connection that transfers load with lap weld, only one fillet weld can be welded, and the pipe lap length L shall not be less than 5 (t1+t2), and shall not be less than 25mm. The size of lap weld leg shall meet the design requirements. 7. The size, spacing and weld height of plug weld and slot weld shall meet the following requirements: (1) The effective area of plug welding and slot welding shall be the nominal area of round hole or long slot hole on the bonding surface. (2) The minimum center spacing of plug weld shall be 4 times of the hole diameter, the minimum longitudinal spacing of slot weld shall be 2 times of the slot length, and the minimum spacing of two rows of slot holes perpendicular to the slot length direction shall be 4 times of the slot width. (3) The minimum diameter of plug welding hole shall not be less than the thickness of the opening plate plus 8 mm, and the maximum diameter shall be the greater of the minimum diameter plus 3 mm and the thickness of the opening piece 2.25 times. The length of slot hole shall not exceed 10 times of the thickness of the opening piece. The minimum and maximum slot width shall be the same as the minimum and maximum hole diameter of plug welding hole. (4) The weld height of plug welding and slot welding shall be the same as that of the base metal when the thickness of the base metal is not more than 16mm; When the base metal thickness is greater than 16mm, it shall not be less than half of the base metal thickness and 16mm, whichever is greater. (5) The size of plug weld and slot weld shall be calculated and determined according to the shear force on the bonding surface. 8. Intermittent fillet welds can be used in secondary components or secondary welded connections. The length of intermittent fillet weld segment shall not be less than 10hf or 50mm, and its clear distance shall not be more than 15t (for compression members) or 30t (for tension members), t is the thickness of thinner weldment. Intermittent fillet welds should not be used in corrosive environment.

Steel structure members are widely used in various steel structure buildings, including steel structure frame, steel truss, steel grid, steel cable structure, cold-formed thin-wall steel structure, light steel structure, steel pile and other types, so how to evaluate the safety performance of steel structure in steel structure buildings? What are the differences of safety evaluation control indexes of steel members in various steel structure buildings? According to the requirements of the relevant codes, the safety of the steel structure members, according to the bearing capacity, structure and not suitable for bearing displacement or deformation of the identification, each inspected member respectively grade identification; For the safety evaluation of steel structure joints and connecting areas, the grade of each joint and connecting areas should be evaluated according to the two inspection items of bearing capacity and structure. For cold-formed thin-wall steel structures, light steel structures, steel piles, steel structures and other steel structures located in industrial areas with corrosive media, or high humidity, coastal areas, unsuitable bearing corrosion should also be evaluated as an inspection item; The lowest level is then used as the security level for the component. 1. Bearing capacity When evaluating the safety grade of steel structural members according to the bearing capacity, the grade of each inspection item is evaluated according to the provisions of Table 1, and the lowest grade is taken as the safety grade of member bearing capacity. The checking calculation of steel structure overturning, sliding, fatigue and brittle fracture shall be carried out according to the relevant provisions of the current national code. The checking of nodes and connecting areas shall include the checking of nodes' plates and connecting areas. Step 2: Structure When evaluating the safety grade of steel structure members according to the structure, the grade of each inspection item shall be evaluated according to the provisions of Table 2, with the lowest grade as the safety grade of component structure. 3. Not suitable for bearing displacement or deformation 4. It is not suitable for bearing rust 5. Safety assessment of cable components 6. Joint safety evaluation of steel grid structure 7. Additional support, nodes, and connections

Today we will talk about steel structural parts (hereinafter referred to as steel structural parts). You may be familiar with steel structural parts. You also know that steel structural fittings include anchor bolts, embedded panels, welded floor cages... What do you know about steel structural parts? Steel structure engineering is one of the main types of building structure. It is one of the more common structural forms in modern architectural engineering. China is the first country to manufacture load-bearing structures with iron, and steel structural engineering is mainly made of steel. As early as the time of Qin Shi Huang (246-219 BC), China already used iron as a simple load-bearing structure, while Western countries started using metal load-bearing structures in the 17th century. From the 3rd to 6th centuries AD, the clever and industrious Chinese people built iron rope suspension Bridges with iron chains. The famous Dadu River iron Cable Bridge in Luding, Sichuan Province, Yuanjiang Bridge in Yunnan Province and Panjiang Bridge in Guizhou Province are all representatives of early load-bearing structures in China. Although China had made outstanding achievements in iron structure in the early period, it remained at the level of iron construction due to the restriction of feudal system and underdeveloped science for more than 2000 years. It was not until the late 19th century that China began to adopt modern steel structures. After the founding of the People's Republic of China, the application of steel structure has made great progress, both in quantity and quality are far beyond the past. Now that we've learned some of the historical stories of steel structure, let's open the door to the kingdom of Steel Structure and see what unique skills their people have. The panel is here to get you. We all know that it is usually made of hot-dip galvanized steel. It mainly plays the role of connecting beams and supporting, which can better play the supporting role. But it also has an important function that we don't know about. Our railway bridge, highway bridge, sea bridge... It was all built by big Brother Panels. Just like the construction of the wharf is completed, it needs to be built on top of the beam, but also need to build support. Steel plates are buried on both sides of the pier. During the sealing construction, the embedded steel plate is first connected into an extension support, and then the support is set on these supports. After introducing the embedded board, guess who the brothers in line are? Yes, they are anchor bolts. He has many brothers whose names vary according to their shapes. Some called 7 character anchor bolt, some called 9 character anchor bolt, some called umbrella anchor bolt, some called welding plate anchor bolt, anchor jaw anchor bolt...... They are screws and rods used to secure various devices to concrete foundations. Generally used in railways, highways, power enterprises, factories, mines, Bridges, tower cranes, long-span steel structures, large buildings and other infrastructure. It has strong stability.

After the loader factory, there is generally a period of about 60 hours of run-in period (some called run-in period), run-in period is according to the technical characteristics of the loader in the early use of provisions. The run-in period is an important link to ensure the normal operation of the loader, reduce the failure rate and extend its service life. Some users due to the lack of common sense of the use of the loader, the construction period is tight, or eager to obtain profits as soon as possible, ignoring the special technical requirements of the new machine run-in period. Even some users believe that, anyway, the manufacturer has a warranty period, the machine failure, the manufacturer is responsible for maintenance. Therefore, the machine in the run-in period for a long time overload operation, resulting in frequent early machine failures. This will not only affect the normal use of the machine, shorten the service life of the machine, but also affect the progress of the project because of the damage to the machine. Therefore, the use and maintenance of the loader run-in period should be paid full attention to. Use and maintenance 1. Because construction machinery is a special vehicle, the operator should accept the training and guidance of the manufacturer before operating the machine, have a full understanding of the structure and performance of the machine, and obtain certain experience in operation and maintenance. The Product Operation and Maintenance Manual provided by the manufacturer is necessary for operators to operate the device. Before operating the machine, read the operation and maintenance manual and perform operation and maintenance as required. 2. Pay attention to the work load during run-in. The working load during run-in shall not exceed 60% of the rated working load, and appropriate workload shall be arranged to prevent the occurrence of overheating caused by continuous operation of the machine for a long time. 3. Pay attention to constantly observe the instructions of each instrument, stop the machine in time to remove the abnormal, and stop the operation before the cause is found and the fault is not removed. 4. Pay attention to check the liquid level and quality of lubricating oil, hydraulic oil, coolant, brake fluid and fuel oil (water) frequently, and pay attention to check the tightness of the whole machine. On inspection, it was found that there was too much shortage of oil and water, and the cause should be analyzed. At the same time, the lubrication of each lubrication point should be strengthened. During the run-in period, it is recommended to add grease at the lubrication point every shift (except for special requirements). 5. Keep the machine clean, adjust and tighten the loose parts in time to prevent the parts from wearing or losing due to loosening. 6. After the end of the run-in period, the machine should be forced to maintain, check and adjust, and pay attention to replacing the oil. In short, the loader run-in period of the use and maintenance requirements can be summarized as: strengthen training, reduce load, pay attention to inspection, strengthen lubrication. As long as attention is paid to and in accordance with the requirements of the loader run-in maintenance, it will reduce the occurrence of early failure, prolong the service life, improve the operation efficiency, the machine will bring you more benefits.

As an important node of traffic network, tunnel plays an important role in the field of traffic and transportation. However, the construction and construction of tunnels is extremely vulnerable to multiple factors, especially in the geological environment. Geological environment quality is very important to tunnel construction. During excavation and construction, engineers must have a good understanding of the geological composition. From the point of view of construction, the choice of tunneling equipment and construction method is the key to make the whole scheme. Geological conditions are a key factor in selecting TBMS The type of engineering and understanding of geological conditions determine the best construction scheme of tunnel boring machine (TBM). Sometimes, in order to minimize the effects of geological complexity and transitions between different geological types, construction plans are adapted to the actual situation. However, the function of a tunnel often determines its cross section and horizontal orientation. As tunnel construction is often unavoidable under mixed geological conditions, certain buffer measures need to be taken, such as subdividing the tunnel alignment and dividing the tunnel sections with relatively consistent geological conditions together, so that the same construction method can be used in the tunnel sections. How to choose an affordable TBM Because TBMS will encounter different geological conditions in a single line, it is necessary to consider the treatment methods under various geological conditions, whose advantages and disadvantages depend on the actual geological conditions and design specifications. At the same time, composite geological buffer measures will also be included in the TBM specification. TBMS are generally single-mode, classified as open or closed earth pressure balancing (EPB) or slurry shield machines. The shield tunneling machine is suitable for the section with similar geological conditions in the whole tunnel. The dual-mode or composite tunnel boring machine developed at present is used in tunnel excavation under the condition of soil rock mixed stratum, and the internal support is usually lined with precast concrete segments. Two-mode TBMS can also be divided into open and closed types. At the same time, earth pressure TBM and mud pressure TBM can be selected to switch between each other. In the construction of soft soil layer and transition zone, TBM uses closed mode; The TBM operates in an open mode in relatively stable formations and rocky areas. When open TBMS are used to excavate rocks and transition zones, detection and grouting are often used to control potentially unstable formations in order to prevent groundwater flooding. As the performance of TBMS continues to improve, the drilling capability in mixed surface conditions is greatly improved and the risk is greatly reduced. However, the real issue is not the suitability and performance of TBMS in complex or mixed formations, but the selection of the right TBM equipment. This often depends on reliable geotechnical investigation, accurate geotechnical baseline profile and geotechnical parameter acquisition, adaptive TBM standards, adaptive TBM design under different geological conditions, and optimal operation of TBM equipment during tunneling. These factors will determine whether the tunnel can be successfully completed under complex geological conditions. The most important thing to realize is that TBM failures in mixed geological conditions can have serious consequences, including water seepage, subsidence, and even collapse. Correct geotechnical evaluation, proper TBM model and the vigilance of the operator to the change of geological conditions are the keys to the success of the project.

1. Sort by the principle of balance It can be divided into mud-water balancing pipe jacking machine, soil pressure balancing pipe jacking machine, mud enrichment type shield pushing machine and multi-function pipe jacking machine. Mud-water balancing pipe jacking machine is the most widely used one at present. Its main advantages are as follows: (1) Suitable for a wide range of soil, including soft soil, clay, sandy soil, gravel soil and hard soil. (2) Strong crushing capacity, large crushing size and large quantity. (3) with an independent water injection grouting system. (4) The jacking speed is fast, the fastest jacking speed is 200 mm per minute. (5) High construction accuracy, up and down left and right correction, the maximum correction Angle of 3.5°. (6) The ground centralized control system is safe, intuitive and convenient. 2. Categorize by caliber It can be divided into large diameter, small diameter and micro pipe jacking four types. Mainly refers to DN2000 above the pipe jacking, people can walk upright; Most of the pipe diameters are DN1000~DN1800. People need to bend down when walking in it. The diameter is mostly DN300~800. In order to ensure the quality of pipe jacking, it is recommended to use DN400 or above pipe jacking construction technology. Micro-pipe jacking machine has huge application space in the reconstruction of old city, environmental protection, can cross roads, Bridges and buildings, crossing ability is strong, no disturbing, small soil disturbance, is the best choice for urban waterlogging control. 3. Sort by jacking length Common distance jacking and long distance jacking are divided by the distance between the jacking pit and the receiving pit. At present, there is no clear regulation on the division of lifting distance. Currently, jacking over 500 meters is common, and jacking over 500 meters can be called long distance jacking. 4. Classification by geological adaptability This classification mainly examines the adaptability of cutter heads to geology and can be divided into flat type, rock type and compound type. Flat pipe jacking machine is suitable for mud, sand and soil, and has poor passability in rock strata and complex geological conditions; The tool head of rock pipe jacking machine is equipped with rock breaking tool head, which is especially suitable for passing through the hard soil layer with large stone content. However, the cost of tool head assembly is too high. At the same time, if there is no corresponding design in the clay layer, it is easy to cause the risk of mud paste tool head locking. Composite pipe jacking machine, as the name suggests, combines the technical advantages of plate type and rock type, and is suitable for rock compound formation. It has excellent performance in different strata and different strength conditions.

Rotary drilling rig is a kind of construction machinery suitable for hole-forming operation in building foundation engineering. It is widely used in municipal construction, highway bridge, high-rise building and other ground foundation construction projects. With different drilling tools, it is suitable for dry (short spiral), wet (rotary bucket) and rock formation (core drill) hole-forming operation. Rotary drilling rig has large installed power, large output torque, large axial pressure, and flexibility, High construction efficiency and multi-function. The rotary drilling rig is suitable for the soil geological conditions in most areas of China, and has a wide range of applications. It can basically meet the needs of bridge construction, high-rise building foundation and other projects. At present, the rotary drilling rig has been widely used in various bored pile projects. It is of great significance to discuss the construction technology of the rotary drilling rig technically. Dry pore-forming process 1. Dry pore-forming characteristics 1. Because the geology is solid and dense, drilling can be done directly without other auxiliary hole-forming materials or equipment. Dry hole forming process is the simplest process in rotary excavation construction, which is characterized by simple process and low construction cost. 2. The dry hole forming process is aimed at hard plastic and solid geology, with or without groundwater, but preferably without groundwater. Before adopting the dry hole forming process, the rock, soil and groundwater conditions must be mastered, and the premise is that the hole will not collapse. 2. Advantages and disadvantages of dry drilling 1. Disadvantages of dry hole forming: Although there is no need to worry about hole collapse, due to the loss of lubrication, softening, cooling and buffering of water and mud, the drilling resistance of some formations is increased, especially for dense dry soil and coarse sand layer, which is difficult to pour slag, exacerbating the loss of drill teeth and vibration of drill pipe. 2. Advantages of dry hole forming: in addition to simple process and low construction cost, under specific geological conditions, due to the softening of mudstone with water, mud lubrication, slip, tooth plugging and lake bottom phenomenon are formed. Dry hole forming can eliminate the above phenomena and improve the shear crushing efficiency. Mud static pressure process 1. Mud static pressure The mud pressure supports the hole wall to prevent construction quality problems and accidents such as hole shrinkage, hole collapse and buried drilling. 2. Three indicators of mud 1. Mud pressure 2. Mud retaining wall 3. Sand content Three sets of mud: mud hydrometer, mud viscometer and sand content tester. Casing process 1. Casing 1. Role of pile casing: protect the safety of pile hole, equipment and personnel. The length of the casing is determined according to the geotechnical and groundwater conditions. Generally, the length of the casing is between 2M and 4M, and the diameter of the casing is usually greater than the pile diameter of 200MM; 2. Lower casing method: reamer, drill bucket, special tooling, vibration hammer; 3. Control requirements: verticality and center deviation of buried pile casing. 2. Casing The casing driver, pipe kneader or full rotary drill, as well as the vibration hammer buries the casing, and the rotary drill bucket follows the pipe in the casing. The casing technology can replace the static pressure technology of mud wall protection, and is applicable to occluded piles, inclined piles, unstable strata and outdoor construction, limited resources (no water and electricity), urban environmental protection construction, etc. Concrete wall-making process The concrete wall-building process of rotary drilling rig is not a normal rotary drilling process. This passive safety process lags behind the mud static pressure and the active safety of the casing process, and has certain operational risks. 1. Concrete walling Generally, in the construction of plateau, mountainous area, backfill and karst cave, due to the lack of groundwater or lack of groundwater, or the lack of water resources, when the dry hole forming process is adopted, the hole will be deviated and partially collapsed, and the C15 concrete will be backfilled into the hole, and the abnormal parts in the hole will be backfilled. After the concrete reaches the initial setting strength, the pick barrel will be used for core drilling. Backfilling concrete into the deviated hole can repair the deviated hole. Backfilling concrete into the local hole collapse position can produce a wall protection layer locally; The hollow karst cave shall be backfilled with concrete, filled with karst cave and drilled for guidance to prevent jamming and deviation. 2. Concrete wall building application 1. Karst cave geology 2. Deviator hole 3. Local hole collapse 3. Precautions for concrete wall construction 1. Lag: the concrete retaining wall has certain advantages when dealing with karst caves and deviated holes, but when dealing with local hole collapse, due to the lag problem, if the drill bucket collapses at the bottom of the hole, it is likely to lead to burying the hole, and similar accidents have occurred in actual construction. Therefore, when adopting concrete retaining wall, it is necessary to fully prepare for prevention, fully understand the geological and hole conditions, and take this process when absolutely sure. 2. Cost: due to the massive use of concrete, when signing the contract, the project department of Party A shall bear the cost of backfilling concrete and pouring excess volume. 3. Construction efficiency: it takes time to reach the initial setting state when concrete retaining wall is used, which results in discontinuous construction of single hole and reduces the construction efficiency.

Drill bit plays an important role in the drilling process of water well rig. The quality of drill bit directly affects the drilling efficiency and the quality of borehole formation. Therefore, we need to pay attention to bit selection and usage. During the drilling process, the operator should pay attention to the drilling use of the drill to make the drill more productive. Several aspects should be paid attention to in water well drill bit: 1. After drilling the drill bit into the structure, the center drilling tool needs to be replaced in time. The bottom of the hole needs to be cleaned first, and then the residue at the bottom of the hole needs to be blown clean. After the bit stops rotating, the drill tool in the well bit should be slowly lifted. It is most suitable when the lifting force is just enough to lift the drill. 2. During the drilling process, the drill bit of the well rig should be summarized. It is also necessary to carefully observe the subsequent casing conditions, learn the specific conditions in the hole, and keep the hole clean when necessary. In addition, the well drill bit shall not be pulled out forcefully during drilling. 3. Sometimes there will be a large amount of rock residue at the bottom of the well drill bit, and the rotating part of the eccentric drill bit will be blocked by rock residue, affecting its production. Compressed air was delivered, the hole was cleaned again, and the hammer was run for a short time before the central drill was lifted again.

Working principle: Construction process: measurement and positioning → pile driver in place → pile lifting and inserting → pile body aligned with middle injection → static driving pile → pile connecting → static driving pile again → pile feeding → pile pressing termination → acceptance → pile driver handing over. Function description: 1. Civilized construction -- low noise, no pollution, clean site, low labor intensity. 2. High efficiency of piling - hundreds of meters per shift (8 hours). 3. Good quality of pile - the eight-way design of pile grabber requires low strength of pile, high quality of pile, simple and reliable operation. 4. The fuselage structure adopts modular design, easy to install, disassemble and transport; The maintenance is more simple and convenient, and the cost is lower. 5. Suitable for pile type diversification -- square pile, round pile, H-type steel pile, etc. 6. Intuitive and reliable - through the instrument data of piling construction, it can directly reflect the resistance of piling and predict the bearing capacity of single pile. 7. Equipped with special crane. Matters needing attention 1. The same pile (section) should be pressed continuously. Pile pressing can be stopped when the gauge reading reaches a predetermined value. 2. Pile driving should check the pressure, pile perpendicularity, pile spacing, pile quality, pile depth. The structures under reaction should be observed more closely. 3. The pressure gauge for the pressure pile must be calibrated before it can be used. The depth of pile and the value of pressure gauge are the basis to judge the quality and bearing capacity of pile, and are also important parameters to guide the construction of pressure pile, which need to be recorded. Overview of static pile driver There is no noise, vibration and pollution in the construction process of static pile method, the construction speed is fast, the site is clean, and the construction civilization is high. Low interference to the surrounding environment, suitable for soft soil areas, urban centers or densely populated areas of pile engineering, as well as the expansion of precision factories.