Vibration-less compaction method of collapsible loess foundation

Abstract

The invention provides a vibration-less compaction method of a collapsible loess foundation. In the method, by adopting a mode of reversely pulled compaction for borehole expansion or transverse static pressure compaction for borehole expansion, compaction areas are formed around compaction boreholes so as to eliminate the original collapsibility of the loess foundation; and semi-rigid pile-forming materials are poured into the compaction boreholes for forming piles so that the formed semi-rigid piles and the compacted loess among the piles jointly form a composite foundation, thereby improving the bearing capacity of the collapsible loess foundation, controlling post-construction settlement of the foundation, and meeting the requirements of civil engineering on high stability of the foundation in China. The vibration-less compaction method is mainly applicable to reinforcement of the collapsible loess tunnel foundation and foundation reinforcement of houses, roads and the like in a collapsible loess area and a mollisol area.

Description

technical field [0001] The invention belongs to the technical field of foundation reinforcement treatment, and relates to a reinforcement treatment method for collapsible loess foundations, in particular to a non-vibration compaction treatment method for collapsible loess foundations. Background technique [0002] The design speed of my country's high-speed railway is 250-350km / h. The design standard stipulates that the line in the tunnel should have high smoothness, the post-construction settlement should not be greater than 15mm, and the differential settlement between different structures should not be greater than 5mm. [0003] In view of the limited construction space and foundation treatment requirements in collapsible loess tunnels of high-speed railways, at present, the main treatment methods are cushion replacement, lime soil (cement soil) impact compaction piles, tree root piles, and high-pressure jet grouting piles. Its main defects are as follows: ①The replacemen...

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Problems solved by technology

Its main defects are as follows: ①The replacement cushion method has a great impact on other construction procedures of the tunnel, and the excavation area of ​​the tunnel foundation is increased during excavation and replacement, and the tamping of the cushion also produces large vibrations; ②Lime soil (cement soil ) The measured wave velocity of vibration during the construction of the impact compaction pile is about 5cm / s, while the wave velocity required for vibration safety is 2-3cm / s, which is likely to cause tunnel cracking and block falling; The loess collapsibility of the intersoil basically has no elimination effect, and the grouting slurry is difficult to control, which will cause environmental pollution and additional collapsible deformation of the collapsible loess tunnel foundation

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