Polymer grouting method for constructing gravel pile

Abstract

A polymer grouting method for constructing gravel pile for reinforcing the soft and special soil foundation includes steps of: (1) pile-position-pore-forming; (2) installing a grouting pipe; (3) putting graded stones; (4) polymer lifting grouting; and (5) pile-forming. By pile-position-pore-forming, putting graded stones, polymer lifting grouting in the reinforcement site and other steps, the injected two-component expansive polymer material expands rapidly after a chemical reaction, and then is solidified with the graded stones for filling in the pile hole from below to above, the blast hole wall rock-soil is expansive compacted and fully integrating with the surrounding rock-soil, thus forming the polymer gravel pile. The present invention can rapidly reinforce the soft and special soil foundation, thereby providing an advanced, highly efficient, safe and practical method for reinforcing the soft and special soil foundation. It has great economic and social benefits and broad development prospects.

Description

FIELD OF INVENTION[0001]The present invention relates to a foundation processing technology, and more particularly to a polymer grouting method for constructing gravel pile for reinforcing soft foundation and special soil foundation.DESCRIPTION OF RELATED ARTS[0002]Since the 1990s, with the steady and healthy development of the national economic construction, China's highways, high-speed railways and other large-scale foundation engineering facilities constructions enter a period of rapid development, and have made remarkable achievements. Due to China's vast territory and complicated variable geological conditions, a large number of highways and high-speed railways pass through the soft soil, the collapsible loess and other adverse geological zones, thus facing very prominent engineering geological problems. The soft soil has physical and mechanical characteristics of large water content, high compressibility, low intensity and small permeability coefficient, when constructing the ...

AI Technical Summary

Benefits of technology

The present invention provides a quick, safe, and strong method for strengthening soft and special soil foundations using a polymer grouting process. This method helps to overcome the shortcomings of existing methods and ensures optimal performance. Overall, the invention offers an effective and practical solution for reinforcing soft and special soil foundations.

Problems solved by technology

Due to China's vast territory and complicated variable geological conditions, a large number of highways and high-speed railways pass through the soft soil, the collapsible loess and other adverse geological zones, thus facing very prominent engineering geological problems.

The soft soil has physical and mechanical characteristics of large water content, high compressibility, low intensity and small permeability coefficient, when constructing the roadbeds in such area, due to long ground foundation cycle, large post-construction settlement deformation, the long-term stability of the roadbeds is seriously affected.

In the collapsible loess, under flooding conditions, the foundation strength of the natural loess is dramatically decreased, and significantly additional settlement is produced, thereby posing a serious threat to the stability of the roadbeds.

The replacement method excavates the surface soft soil to backfill the hard coarse grained materials and tamp for improving the bearing capacity of the foundation, and is mainly adapted for dealing with the shallow weak foundation and uneven foundation with the depth of 2-3 m. The drainage consolidation method adopts the heap load or vacuum preloading to discharge pore water in the soil for improving the soil strength, and partially or totally eliminating the foundation settlement, and is not adapted for the foundation soil with low water content.

The chemical reinforcement method adopts the perfusion pressing-in, high-pressure injection, or mechanical stirring to cement the cement or chemical grout with the soil particles together for improving the physical and mechanical properties of the foundation soil, and it has complex construction process, environmental contamination and high cost.

The reinforced method lays layer-by-layer the reinforced cushion consisting of earthwork synthetic materials and sand stone as the foundation bearing layer, uses the friction function between the reinforcement and soil to improve the tensile and shear performance of the soil, and is not adapted for dealing with a wide range of deep soft foundation.

Although the gravel pile reinforcement method has the outstanding advantages, and is increasingly widely used, it still has some deficiencies for the demand of the foundation treatment engineering which are mainly manifested in: (1) adopting the high-pressure water punching cutting pile technology in the vibroflotation process, which is not adapted for the foundation treatment engineering with higher sensitivity to water; (2) more complex construction process and difficult to control the construction quality; (3) greater disturbances to the foundation in the construction process and polluting the environment due to produced large amounts of liquid waste; (4) large construction equipment, high energy consumption, poor applicability and high requirements on the construction site; (5) the vertical bearing capacity and the settlement of the gravel pile largely depending on the binding force of the surrounding soil to the gravel pile, wherein if the surrounding soil is soft, the binding force of the surrounding soil to the gravel pile is poor, the vertical bearing capacity of the pile body is restricted; (6) the pile body consisting of granular mixture materials, wherein almost no cohesive force exists between the particles, so that the horizontal bearing capacity of the pile body is poor, the composite foundation is invalid due to the sheared gravel pile while withstanding the horizontal loads under special circumstances.

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