Mechanism Analysis of Vacuum Preloading

Mechanism Analysis of Vacuum Preloading
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The construction process and reinforcement effect of this method are introduced. Through the analysis of technical indicators, the use of vacuum preloading has achieved a good expected reinforcement effect. It is a ground reinforcement method that uses vacuum to reinforce the soft soil foundation. The method uses vacuum to form a negative pressure in the reinforcement zone, which can speed up the consolidation and settlement rate of the foundation soil, increase the strength of the soil, and at the same time solve the stability problem in the embankment construction and shorten the filling of the embankment. The construction period is a soft soil foundation treatment method that is being gradually promoted in recent years. At present, the process technology of vacuum preloading in China is at the leading international level in terms of vacuum degree and large-area reinforcement, and its application is more and more extensive. Vacuum Preloading Method and Strengthening Mechanism Introduction Vacuum preloading method to treat the foundation, firstly laying two or so thick sand cushions and drainage pipes on the surface of the original foundation as a horizontal drainage body, and then hitting a bagged sand or plastic drainage in the soil. The plate is hereinafter referred to as a sand well as a vertical drainage body. The airtight film is laid on the sand cushion of the surface of the soft soil foundation to be reinforced. The film is buried in the earth, and the air buried in the sand under the film is extracted by the pipeline buried in the sand mat to form a relative Negative pressure, due to the large permeability of the sand well, the negative pressure can be rapidly transmitted to the sand well, thereby creating a pressure difference between the sand well and the soil around the sand well, so that the pore water in the soil flows into the sand well and is discharged. To achieve consolidation. The vacuum preloading system consists of a vacuum pumping system and a drainage exhaust system. In the process of vacuuming, the soil in the reinforcement range is effectively sealed by the sealing membrane and the surrounding soil. The air pressure in the seal is gradually reduced through the vacuum sealing. The first sand cushion, then the sand or plastic drainage board, and the vertical drainage The channel will transfer to the deep layer, so that the central atmospheric pressure of the fixed soil will be reduced along with the highway engineering in Hangzhou, and the atmospheric pressure difference will be formed simultaneously with the drainage channel. Due to the pressure difference between soil and sand cushions and sand wells or plastic drainage boards, seepage occurs, so that the pore water stress in the soil is continuously reduced, and the effective stress is continuously increased, which promotes settlement deformation of the foundation and consolidation of the soil. This shows that the process of vacuum preloading to reinforce the foundation is actually the process of consolidating the soil by reducing the pore water pressure and increasing the effective stress under the condition that the total stress is constant. In addition, since the pore water stress in the soil is a ball stress, the increment of effective stress in all directions should be equal during the reduction of pore water stress, so the soil not only causes vertical settlement and deformation, but also occurs lateral contraction deformation. This is very beneficial to the stability of the roadbed.

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