Method of composite electroosmosis, vacuum precipitation and vacuum preload reinforcement foundation and device thereof

Abstract

The invention discloses a method for strengthening the foundation with composite electroosmosis, vacuum dewatering and vacuum preloading, and aims to provide a method for foundation treatment, especially for various types of soil with a permeability coefficient of <10-5cm / s in a large area. Methods of strengthening soft soil foundations. The device used in the method of the present invention adopts a composite pipe and a redundant film with openings or a mesh cap eye film or a mesh cap eye vacuum film with a connector. The method of the invention is a method for reinforcing the foundation that combines electroosmosis, vacuum dewatering and vacuum preloading, and can be implemented in parallel. It has the advantages of balanced treatment, simple and convenient construction, short project time, and high cost performance.

Description

technical field [0001] The invention relates to a large-area foundation treatment method and its device, more specifically, the invention is directed to the treatment method and its device for shallow and deep ultra-soft soil foundations. Background technique [0002] 1) Vacuum preloading technology [0003] Vacuum preloading is a method gradually developed in my country after the 1980s, mainly for soft soil with a permeability coefficient ≥ 10. -5 cm / s, a large-area soft foundation reinforcement technology, has mainly been developed into vacuum preloading, surcharged preloading and other technologies at present. [0004] However, these technologies have some traditional shortcomings that are difficult to overcome, so that their in-depth promotion and application are limited to some extent. The main shortcomings are as follows: [0005] 1. Vacuum preloading, the range of soil that can be reinforced is extremely limited: for permeability coefficient <10 -5 cm / s soil, it...

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Problems solved by technology

[0004] However, these technologies have some traditional shortcomings that are difficult to overcome, so that their in-depth promotion and application are limited to some extent. The main shortcomings are as follows:

[0005] 1. Vacuum preloading, the range of soil that can be reinforced is extremely limited: for permeability coefficient -5 cm / s soil, its reinforcement is basically powerless; for the permeability coefficient ≥ 10 -5 cm / s soil, only partial reinforcement can be effective

[0006] 2. Due to the traditional vacuum preloading, only the free water in the soil can be discharged, but the bound water cannot be discharged. The water content of the treated soil is still above the liquid limit, so the treated soil layer is difficult to be used as The hard shell layer cannot be further processed and the bearing capacity of the foundation can be improved by foundation engineering techniques such as dynamic compaction and soil bags

[0007] 3. Due to the vacuum membrane, the sand cushion under the vacuum membrane, the vertical mixed drainage vacuum system, the sealing ditch, etc., a unified and integral vacuum system is formed between the soil and the vacuum system, and the vacuum transmission efficiency of this vacuum system is low. Problems and deficiencies such as uneven distribution of vacuum degree and inaccurate monitoring of vacuum degree greatly affect the effect of vacuum preloading

[0008] 4. Since the traditional vacuum preloading system uses a single integral sealing membrane, in order not to puncture the vacuum membrane, this will also lead to some shortcomings: ①The vertical drainage vacuum system can only use a flexible system, and the flexible vertical mixed drainage The vacuum system cannot be reused; ②The horizontal drainage system in the sand cushion under the vacuum membrane may be broken by the uneven settlement caused by vacuum preloading, and may puncture the vacuum membrane, and this arrangement also increases the horizontal drainage The complexity and uncontrollability between the system and the sealing groove

[0010] 6. Due to the constraints of comprehensive factors such as equipment, the time required for traditional vacuum preloading is very long, 3 months or more, the processing cost is high, and the quality is unstable

[0013] 1. Since the open-air electroosmotic precipitation treatment is performed first, and then low-energy dynamic compaction is performed, for rainy areas, during the electroosmosis process, the electroosmotic effect will cause a large number of distributed cracks in the soil. Before the soil can be compacted, the rainfall has recharged the soil, which greatly offsets the effect of electroosmosis, making the previous work basically ineffective

[0014] 2. Due to the electroosmotic dewatering treatment in the technological process, and then several repetitions of low-energy dynamic compaction, the construction is difficult and more complicated

[0015] 3. High-pressure water punching is used in the hole forming construction, which has defects. The secondary hole forming will lead to the recharge of on-site punching water, which will affect the existing site electroosmosis effect

[0017] 5. The degree of mechanization of the construction process is not high, and it relies heavily on technicians, so it cannot adapt to large-scale soft soil treatment

[0018] 6. Low-energy spot ramming will cause the entire reinforcement site to be unevenly loaded on the plane distribution and depth distribution, resulting in uneven foundation

[0019] 7. Since low-energy dynamic compaction is a fast-loading dynamic load, the effect of pore pressure dissipation in the soil is limited, which affects the effect of foundation treatment

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