Reinforcing method for terrace loess foundation and built variable-rigidity composite pile composite foundation

Abstract

The invention discloses a reinforcing method for a terrace loess foundation and a built variable-rigidity composite pile composite foundation. The reinforcing method comprises the steps that an area needing to be reinforced is leveled, and shallow pits are dug; upper-layer holes are generated, lower-layer holes are drilled according to the water content of a loess layer below an A layer, and pile holes are formed; rigid pile material mixtures are poured and vibrated, then flexible pile material mixtures are filled, layered tamping is carried out till the pile holes are filled, and variable-rigidity composite piles are built; the second variable-rigidity composite pile is built; all the variable-rigidity composite piles are built in the reinforced area; bulk materials are laid in the shallow pits; and after cement is fully hardened, the terrace loess area foundation is reinforced. The variable-rigidity composite pile composite foundation comprises the multiple vertically-arranged variable-rigidity composite piles, each variable-rigidity composite pile is formed by fixedly connecting an upper pile body and a lower pile body which are arranged up and down, and the top ends of all the upper pile bodies are fixedly connected through a cushion layer. According to the reinforcing method, on the premise that the sedimentation requirement is met, stress concentration of the bottom of the foundation is reduced, and the bottom of the foundation is prevented from being punched.

Description

technical field [0001] The invention belongs to the technical field of terrace loess foundation reinforcement, and relates to a terrace loess foundation reinforcement method, and also relates to a variable stiffness composite pile composite foundation constructed in the foundation reinforcement method. Background technique [0002] The engineering geological conditions of the terraced loess in Northwest China are special. Affected by the erosion of rivers, the uplift of the Qinghai-Tibet Plateau, and the intermittent uplift of the Loess Plateau, multi-level loess terraces are formed. The bottom of the terrace is bedrock, and then there are round gravel and gravel layers, and the uppermost part is loess deposits of different ages. The loess in the upper part of the terrace is relatively dry, with a small water content and a certain degree of collapsibility. With the increase of depth, the water content of the loess increases linearly, and the bottom reaches saturation. At pr...

AI Technical Summary

Problems solved by technology

According to the survey report, most of the foundation settlement deformation in the loess area in Gansu comes from the deep part of the loess layer, and both the dynamic compaction method and the compaction pile method are limited by the reinforcement depth, so it is difficult to control the settlement well

The DDC pile method is not suitable for soil layers with high water content, and cement-soil piles will also be difficult to form piles in layers with high water content.

Images