Vacuum prepressing seepage consolidation method

Abstract

The invention relates to a vacuum prepressing seepage consolidation method. The vacuum prepressing seepage consolidation method is characterized by comprising the following steps that firstly, an integrated well point plastic vacuumizing system is arranged, specifically, insertion construction of integrated well point plastic vacuumizing pipes is conducted, so that an integrated well point plastic vacuumizing pipe mesh is formed; the integrated well point plastic vacuumizing pipe mesh is connected with a main pipe and a vacuum pump, so that the integrated well point plastic vacuumizing vacuum system is formed; and secondly, vacuum prepressing is conducted, specially, cofferdam diking is conducted around an area to be reinforced, a water source around the outside of the reinforced area is pumped into a cofferdam in the area to be reinforced in the early stage, then vacuum prepressing is conducted through the integrated well point plastic vacuumizing system, pumped underground water is completely recharged to the surface of the area to be reinforced during vacuum prepressing, and after the surface of the area to be reinforced is completely immersed in water by a certain height, water-covered prepressing, water-covered sealing and water-covered seepage are achieved. The vacuum prepressing seepage consolidation method has the advantages that operation is easy, the cost is low, and the construction effect is good.

Description

technical field [0001] The invention relates to a soft ground treatment method, in particular to a vacuum preload seepage consolidation method. Background technique [0002] According to 7.1.1 of the "Code for Design of Building Foundations" (GB5007-2011), weak foundations refer to foundations mainly composed of silt, muddy soil, flushing soil, miscellaneous filling soil or other highly compressive soil layers. Before building construction on the weak foundation, it is necessary to consolidate the weak foundation first. The conventional consolidation treatment methods are as follows: [0003] 1. Conventional vacuum preloading reinforcement. Conventional vacuum preloading reinforcement "on land and under water in rivers, seas, lakes and swamps" soft soil foundations all need to be laid with sealing film and sand cushion, but there are the following disadvantages: [0004] 1. The construction of large-area sealing membranes is difficult, and vacuum preloading on land requires...

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Problems solved by technology

[0004] 1. The construction of large-area sealing membranes is difficult, and vacuum preloading on land requires a lot of manual laying of membranes with a low degree of mechanization, especially the construction of underwater vacuum preloading sealing membranes is more difficult;

[0005] 2. The PVC sealing film has low strength and is easy to be damaged and leak air. The cost of the second layer of sealing film and the first layer of geotextile is high, and it is difficult to find the air leakage point;

[0006] 3. A large number of PVC sealing films are not environmentally friendly;

[0007] 4. The surface under the film can reach a maximum negative pressure of 80kPa, and the negative pressure transmission loss to the deep part of the soil layer is fast. Generally, the loss of negative pressure per meter to the deep part is about 10kPa. The effective reinforcement depth is shallow;

[0008] 5. The loading surface is on the original ground surface or the backfilled land surface. Even if the surface sealing film does not leak, the slow air leakage of the shallow soil around the reinforcement area cannot be ignored, especially in the case of long-term loading for about 90 days, when the groundwater level drops to The degree of air leakage in shallow soil around a certain degree of reinforcement area is even more worrying

[0009] 2. The improved vacuum preloading reinforcement has the following disadvantages:

[0010] 1. The sand-removing cushion layer is changed to the mode of direct connection of plastic slabs with hand-shaped joints, and the mode of indirect negative pressure transmission is changed to direct negative pressure transmission mode, but it still needs a sealing film, and the maximum negative pressure loading surface is still on the surface;

[0011] 2. The sealing layer is formed by blowing and filling mud, or the vacuum branch pipe is directly connected to the plastic discharge into the soil for about 1.5 meters, or the vacuum filter tube is about 3 meters underground, and the side blister row replaces the sealing film. The dredging fill mud loses water, consolidates and cracks, the groundwater level drops rapidly, and the sealing effect is greatly reduced;

[0012] 3. The ultra-soft soil for land reclamation cannot be mechanically constructed. First, artificially insert the shallow layer of plastic drainage vacuum preloading, and then do deep vacuum preloading after the foundation strength is suitable for mechanical construction. The principle and process of conventional vacuum preloading are almost the same, only the simple difference between manual and mechanical, the process is more complicated, the cost is high, and the efficiency is low;

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