The technique of impermeable wall construction is shallow

China Paint Online News Information: Impermeable wall construction technology involves many aspects, such as deep mixing pile continuous wall construction technology; Underground continuous thin impermeable wall construction technology; The key technology of impermeable wall construction; Saw groove process and construction technology, these technologies have their own applicable conditions, according to the actual situation of the project and the characteristics of these technologies, choose the appropriate construction technology to achieve the desired effect.
first, deep mixing pile continuous wall construction technology
deep stirring water soil impermeable wall using single-axis, multi-axis deep stirring pile machine construction. The principle is to drill a deep pile machine to a predetermined depth, inject cement slurry into the hole, use a spiral drill bit for stirring, as far as possible to make the soil and cement slurry forced to mix evenly and condense, forming a water and soil column, connected to each other into a wall, play a role in impermeability.
1. Construction method of the two-powered three-headed deep mixing pile machine
The mixing pile machine is positioned according to the shaft axis of the impermeable wall, and the skew rate should be less than 5 inches according to the connecting tube on the pile machine. The middle deviation of the pile pair is not greater than 50mm.
cement slurry preparation system, cement slurry is strictly filtered, in the mortar mixer and the mixer before each set a filter. Pipeline connection: Use pressure hose to connect the mortar pump outlet with the deep mixer's slurry pipe inringing.
to run. Adjust the stirring speed, not more than 10% of the specified value of the design; Adjust the lift speed, generally controlled at about 1m/min; The feed line and the water supply line are smooth; Various instruments should be displayed correctly and the detection data accurate.
the spray and sink. Start the slurry pump to the drill bit, then start the host, so that it is turning forward, and select the drill bit to push down the stop until the design depth.
stir to lift. When drilling into the design depth, stop drilling to fill cement slurry 30s, until the hole back to the slurry, reverse rotation lift drill pipe, continue to fill the slurry, keep the hole slightly back to the slurry. When the mixing head is raised to the top of the design pile, stop lifting, stirring, spraying for a few seconds, to ensure that the pile head is uniform and dense.
stir again. Stir, spray for a few seconds after the mixing head is turning forward downwards to the design depth, and then reverse rotation to the top of the pile. At this point, the amount of perfusion cement slurry is properly controlled (which is based on not blocking the lines).
the cleaning lines. Inject water into the hopper, turn on the cement slurry remaining in the mortar pump cleaning line, until the mixing head is filled with water and manually remove the soft soil that is attached to the mixing head. The machine is then transferred for the construction of the next pile.
2. Single-head deep mixer construction method
Single-head machine and multi-head machine construction steps, pile machine into a wall, single-head machine than multi-head machine more than a cycle, and regard not in order. Each transfer machine 44.4cm, eventually into a wall thickness of 32.5cm.
3. The application scope of the impermeable wall of the deep stirring method
The deep stirring method has strong applicability in soft soil foundation reinforcement and impermeable treatment, and its carrying capacity and impermeable performance can meet the normal requirements after treatment. Under the current construction conditions, considering the guarantee of economy and quality, the scope of application should be loose sand, powder sand, powder clay and soil layer containing a small amount of gravel, even soil frame or cave can also be constructed. However, it is used with caution in gravel layer, soil with higher organic matter content and clay layer with less water content.
4. Technical characteristics of deep stirring anti-penetration wall
High efficiency of construction work: when the average construction efficiency can reach 13.2m/unit, it is a method of building walls faster with various impermeable techniques; The cost of building a wall is low: the cost of building a wall is 1/5 of the high spray, is 1/3 of the concrete impermeable wall; The construction process is simple: no grooving, no holes, walls, backfilling, solidity and so on, more importantly, do not destroy the dam; The wall effect is good: the wall thickness is uniform and continuous, the joint is less, the wall thickness meets the requirements of impermeability (the diameter of the pile machine head is 400 to 500mm), the wall depth can reach 22m; No pollution, low noise, etc.
, impermeable wall construction key technology
1.
the key technology of combining drilling rig slotting method, water shooting method, deep mixing pile, etc. is verticality. Verticality is related to whether the impermeable wall is built on the same wall axis. Therefore, during the construction period, the left and right deviation, axis deviation, hole slope data should be in accordance with operating procedures and regulations, carefully observe the record. If the skew is found, immediately take steps to correct it to ensure that the impermeable wall is on the same axis. Otherwise, it is easy to break the wall or the bottom of the wall is not strictly connected, the construction gap is too large to cause concentrated leakage phenomenon.
2. Wall seam bridging treatment
The connection between the concrete wall and the concrete wall should be repeatedly cleaned up and down the original poured wall joint, to ensure that there is no mud at the connection. The wall is parallel to the wall, and the length of the tie should be 1 to 2 m. If the connection is found to be not strict, the leakage channel, drilling rig drilling and pouring concrete method can be used to close the leakage, to achieve the purpose of intercepting seepage.
3. The
is prone to the phenomenon of widening and collapsing holes by relying on mud wall protection process during construction. The main reason for the expansion and collapse of holes is that the soil layer contains a layer of material, a layer of powder sand, holes, cracks and so on. To solve the above problems, the main measures that can be adopted are: First, strictly control the concentration of wall mud, if necessary, pulping can be proportionally appropriate addition of bento-earth. Second, the encryption placement isolation body, increase the support force. Third, shorten the length of wall pouring and reduce the immersion time.
4. Drilling and lifting of deep mixing piles
The mixing pile is an impermeable wall formed by pumping cement paste through a high-pressure slurry system into the soil and stirring them evenly. Its drilling and lifting speed are directly related to wall thickness, width, strength and impermeability. Therefore, in the construction work, the robot should strictly implement the operating procedures, process. The original record and construction log should be recorded in detail and the control and supervision of key operations should be strengthened.
, underground continuous thin impermeable wall construction technology
underground continuous thin impermeable wall construction of several works and equipment drilling grout into the wall. Its main working principle is to drill the grout and stir it into a wall. One device is a multi-head small diameter deep stirring once into a wall pile machine. The equipment is mainly composed of hydraulic step performance walking chassis, special guide frame, six drill pipe, chain and so on. The equipment structure is reasonable, the wall building efficiency is high, the maximum wall depth is 22m. Another kind of equipment is the double-powered multi-head deep mixing pile machine. Mainly by the hydraulic step performance walking chassis, special guide frame, wall-building, three six-bit mixing drill and other components. Dual-power drive, with drilling multi-stage speed control, drill pipe center from adjustable, three tubes respectively metering grout, vertical precision control method advanced, small environmental impact and other advantages, the maximum wall depth of 21m. Hydraulic grip ultra-thin concrete impermeable wall. The wall thickness is generally 25 to 30cm, the selection of equipment for foreign production of CH-60 and CH-80 hydraulic grab, slotting up to a maximum depth of more than 70m. Because its thickness is only 1/3 to 1/2 of the conventional concrete impermeable wall, in general, hydraulic grabs can be used to dig directly into the groove, the degree of construction mechanization and efficiency greatly improved, and can save a lot of concrete and other related materials, the cost of the project greatly reduced. At the same time, the verticality and continuity of the wall can also be better guaranteed, impermeable effect can fully meet a variety of design requirements, truly reflects the concrete impermeable wall impermeable performance, short construction cycle, low cost, quick results and other advantages.
4, sawing groove method wall-forming process and construction technology
the wall-forming process is the use of saw-groove machine's knife rod in the pilot hole, with a certain inclination side for up and down cutting movement, while along the groove hole axis according to The formation condition moves forward at the speed of 0.8 to 1.5 m/h, and the soil cut by sawing can be discharged out of the groove by the anti-cycle slag system or positive circulation method, and a groove hole is formed by using mud wall protection. When the sawing machine slot length of 6 to 11m, the use of earth cloth isolation to divide the groove hole into slotting section and pouring section, and then clear the hole, plastic pouring to form a width of 0.2 to 0.3m impermeable wall. The saw slot machine is mainly composed of walking chassis, power and transmission system, knife rod and bracket pressurized system, slag discharge system, lifting facilities and electrical control system. According to the mode of transmission there are mechanical and hydraulic two kinds of sawing machine. Saw slot machine can be replaced and combined according to different specifications of the knife rod, so that the slot width of 0.2 to 0.5m, depth of 40m. The advantages of sawing groove into a wall process and construction equipment is continuous grooving, high efficiency, good wall quality, and wall depth, adapted to clay, sand and pebble particle size less than 100mm gravel formation. Because the method has the characteristics of continuous grooving, it can also be used to build walls with self-condensing mortar and curing mortar technology, forming impermeable walls with different strengths and different impermeability indicators.
, special treatment technology
1. If the guide wall is seriously deformed or the bottom collapses, the following treatment methods should be taken: (1) the damage site should be rebuilt or other safety construction measures taken;
2. If the formation is seriously leaking, the leak-blocking material should be filled quickly and, if necessary, the groove holes may be backfilled.
3. When the catheter is blocked, pulled out or leaky during concrete pouring, the following methods must be used: (1) all the catheters are pulled out, flushed, and re-set, the mud in the drain pipe continues to pour;
4. When the steel cage floats in the concrete pouring process, the following measures need to be taken: (1) the purchase depth of the catheter should be adjusted in time and the rising speed of the concrete surface should be reduced appropriately;
5. In the process of concrete pouring, the following methods can be selected for treatment: (1) chiseling the concrete that has been poured into the hole, re-pouring;
References:
, Xu Zanyun, Wu Xueqin, underground continuous wall joint form and leakage analysis 2008 No. 30
Wang Weidong, Dian Guoen, Huang Shaoming, underground continuous wall prefabriited joint technology research and application; Journal of Underground Space and Engineering; Issue 03 of 2007