1. The preliminary preparation work mainly includes three parts during implementation: material preparation, equipment preparation, and construction condition preparation. The construction materials may have different needs according to different construction methods, but generally speaking, the selected plastic drainage boards are factory processed and formed finished products. When selecting materials, it is important to note that the tensile strength should be greater than 10 MPa, the elongation should be greater than 2% but less than 10%, and it should be able to withstand a tearing shear force of at least 300 Newton. In addition, it is necessary to meet the corresponding permeability and size shape. There are many optional equipment during construction. At present, the most important one is the type IJB-16 plate inserting machine or the simple plate inserting machine transformed by changing the working device of crane and Pile driver. In addition, necessary pumping equipment and fixed equipment are also needed. The working conditions should ensure that the foundation environment is basically stable without significant changes in soil properties. And it is necessary to ensure good drainage in the construction area.

 

2. There are differences in the basic construction process division methods, so the construction processes obtained from different perspectives are not the same. But basically, it includes leveling the construction ground, placing sand layers on the lower layer, placing tools in place, plastic drainage board boots, inserting pipe sleeves, pulling out sleeves, cutting plastic drainage boards, shifting tools, placing sand layers on the upper layer, and layered sand filling and preloading. While paving the lower layer of sand, it includes checking the quality and thickness of the sand layer. After the machines and tools are in place, the construction personnel should strictly check the distance between the boards, neither too far nor too close. When inserting the pipe sleeve, pay attention to checking the length of the plate and avoid any breakage. The more complex part is the insertion board and the cutting of the drainage board head. When inserting the board, first place the board inserting machine in place, and then use vibration to make the drainage board reach the specified depth. The drainage board should be connected to the anchor shoe at the end and pass through the sleeve. When pulling out the sleeve, the drainage board and anchor shoe should be left in the soil together, and then cut the plastic drainage board short. In the operation of cutting plastic drainage boards, a 20 centimeter board head should be left above the ground. Then, the 20 centimeter sand next to the board head should be excavated, and the board head should be cut off. This completes the insertion construction of a board. Then, at an appropriate position above the foundation, apply a certain amount of surcharge to form a preload. The surcharge can be selected from materials that meet the requirements but are easy to operate. After a certain period of time, the drainage work can be carried out.

Construction precautions for the preloading method of plastic drainage board for treating foundation

 

The positioning of plastic drainage boards includes position and depth, and the positioning requirements for drainage boards in engineering are relatively strict. The pile position of the drainage board should be accurate, in accordance with the design and national standards, and errors should be minimized during pile driving. If necessary, accurate measurement and positioning can be carried out first, and if conditions permit, detection can be carried out during the insertion of the board, and the inclination angle and depth can be adjusted at all times. The installation depth of plastic drainage boards should be adjusted appropriately according to the needs of the project, and also under different foundation conditions, so that preloading can have a good effect. The length of the drainage board exposed to the ground after cutting the strip can be adjusted according to different construction requirements, but all adjustments must be made in accordance with relevant specifications.

 

The plastic drainage board should be firmly connected to the pile tip, and it is absolutely prohibited to remove the drainage board from the board position or cause deviation of the drainage board due to excessive friction during pipe pulling, which will affect the drainage effect. During the pipe pulling operation, it is important to pay attention to the length of the plastic drainage strip of the pipe strip meeting the specifications. When the board is pulled out more than two meters, it should be reinforced with a new board. The treatment of broken ends of plastic drainage boards should be based on reducing the resistance between conduits, using internal overlapping connection technology, and strictly controlling the overlapping length to ensure that the overlapping length is within 200 millimeters, which can ensure smooth water delivery and meet the requirements of overlapping length. And during the process of wrapping plastic bags, it is necessary to minimize the entry of sludge and avoid clogging the water delivery holes with sediment, which may affect the drainage effect of the plastic. The size and shape of plastic drainage boards should be as suitable as possible for the site environment. If necessary, secondary processing can be carried out, but attention should be paid to ensuring the strength and functional integrity of the drainage board.

 

Stacking materials are generally used in the second level of load, with the first level of load mainly being manual operations and supplemented by mechanical equipment when necessary. The selection of stacking materials is generally based on sand and gravel, preferably building materials that can be used. Strict control should be exercised over the area of the surcharge, with the top area of the surcharge being greater than the bottom area of the building, in order to ensure sufficient surcharge pressure and maximize drainage. The area of the loading base should also be expanded to a certain extent, but it should not be too large. According to the force chain transmission rules of particulate matter, the bottom pressure of the stacked material is approximately uniformly distributed within a certain area centered on the center of gravity projection of the bottom surface. In order to evenly distribute the preload generated and ensure uniform settlement of the foundation, it is necessary to appropriately expand the area covered by the bottom surface. During the construction process of pile loading, the rate of load application needs to be controlled to ensure that the foundation is in a stable state under all levels of load, while also avoiding damage to the foundation caused by excessive pile loading. To adopt a graded loading scheme for stacking, there should be a certain time interval between each level of loading, and data such as pore pressure, vertical deformation, and displacement of edge piles should be tested daily. The loading speed should be controlled according to the data. If the vertical deformation exceeds ten millimeters per day and the displacement of edge piles exceeds five millimeters, the loading speed should be adjusted to ensure the quality of the project.

 

By combining with actual construction methods, the basic process of plastic drainage boards during construction and the basic precautions for plastic drainage boards under preloading construction are briefly described. Overall, the plastic drainage board preloading method is simple to operate, effective, and easy to analyze in theory, with certain theoretical guidance. It is worth promoting and applying in engineering practice.