Combined method for fastening soft soil ground by dual vacuum prepressing and dynamic extruding method

Abstract

The invention relates to a soft soil foundation method combined with double vacuum preloading and dynamic compaction, which is suitable for land reclamation or low-lying land filling projects in which large-area soft soil is reinforced and its elevation is raised by dredging and filling mud. It includes the following process steps: Low-level vacuum preloading: first build cofferdams, dredge and fill the mud layer at a certain elevation, lay geotextiles and bamboo layers, insert plastic drainage boards vertically, lay vacuum horizontal pipe networks, install vacuum preloading systems and blow Mud seal layer, mud seal layer thickness 0.8 ~ 1.5m, vacuum preloading system vacuum preloading; high vacuum well point dewatering: high vacuum well point dewatering system is arranged on the mud seal layer, first vacuum dewatering, well point pipe is removed ; Low-energy dynamic compaction: lay a layer of filler on the mud seal layer, and perform the first pass of low-energy dynamic compaction; after 2 to 3 rounds of "high vacuum well point precipitation-low-energy dynamic compaction"; vibration rolling, leveling the site. The invention realizes the simultaneous treatment of the soft soil foundation and the mud layer raised by dredging filling, and the treated site has high degree of consolidation, short consolidation period and high strength after consolidation.

Description

Technical field: [0001] The invention relates to a comprehensive reinforcement method for large-area soft ground. Suitable for silt, silt soil foundation. It is especially suitable for land reclamation or low-lying land filling projects where a large area of ​​soft soil is reinforced and its elevation is raised by dredging and filling mud. Background technique: [0002] With the reform and opening up, construction land is becoming more and more scarce. For this reason, land reclamation is generally carried out in various coastal areas. These beaches not only have low bearing capacity, but also have a low ground elevation. According to the traditional method, sand blowing and earth-rock filling are required first. Consolidate the soft soil foundation and backfill materials on the beach. The traditional method is not only expensive, but also has a long construction period and seriously damages the ecological environment, which is not conducive to sustainable development. In...

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Problems solved by technology

But this process method itself also has some obvious shortcomings so that the implementation and popularization of this process method are limited to a large extent, and its main disadvantages are:

[0003] 1. The reinforcement effect is not ideal

[0004] In large-area reclamation projects, due to factors such as the soil properties and fluidity of the mud, the flatness of the site, and the position of the mud blowing port, the thickness of the mud seal layer is uneven. If the mud seal layer is too thin ( 80cm), there will be a certain thickness of unconsolidated soft interlayer between the layers, and the above two points directly affect Reinforcement effect

[0005] 2. The strength of the reinforced soft soil foundation is not high

[0006] The vacuum negative pressure of the low-level vacuum preloading method is generally 80Kpa, and the thickness of the mud seal layer on it should not be too thick, and the self-weight stress of the corresponding mud seal layer is small, so the combined preload of the two is not large. The consolidation index after preloading is low, resulting in low strength of the reinforced soft soil foundation

[0007] 3. The consolidation index after reinforcement is too low

[0008] Since the mud seal layer is mainly consolidated by natural evaporation, and the mud seal layer mainly composed of clay particles is difficult to consolidate naturally, resulting in a low consolidation index; especially when the mud seal layer is thick, due to the unconsolidated The existence of soft interlayer makes its consolidation index lower

[0009] The above-mentioned shortcomings have largely restricted the implementation and promotion of this process.

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