A construction method of collapsible loess foundation

Abstract

The invention discloses a construction method for a collapsible loess foundation. The construction method comprises the following steps of: firstly, performing foundation treatment on a loess field with collapsibility by using a super downhole dynamic consolidation (SDDC) pile; secondly, collecting undisturbed soil on site, normally performing an indoor experiment to measure an inter-pile soil compaction coefficient and an SDDC pile body compaction coefficient, evaluating the collapsibility, and if any one of the three indexes cannot meet a design requirement, performing pile compensation construction on the SDDC pile until the design requirement is met; and finally, pouring the pile and mudjacking. The method has the advantages of economy, environment friendliness, high treatment depth, good treatment effect, large bearing potential, high complicated load resistance and the like. By application of the method, various side effects caused by the collapsibility of the deep collapsible loess field can be eliminated, and requirements of upper-part high rise buildings on the bearing capability and settlement of the foundation can be met.

Description

technical field [0001] The invention relates to the field of building foundation treatment, in particular to a construction method for jointly treating loess foundation collapsibility by adopting SDDC piles and cast-in-situ pile post-grouting technology. Background technique [0002] Loess foundation treatment problems are often encountered in Northwest and North China, usually including low-humidity collapsible loess with the main purpose of eliminating or reducing the damage of collapsible deformation, and at the same time need to improve the foundation bearing capacity, and high-humidity soft loess (Especially saturated loess, which is mostly transformed from collapsible loess saturated with water, saturation S r ﹥80%) are ground treatment issues aimed at improving the bearing capacity of the ground and reducing harmful compression deformation. Since the engineering characteristics of the latter are mostly similar to those of ordinary cohesive soils, the compression defo...

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Problems solved by technology

[0005] Among the above treatment methods for collapsible loess foundations, method (1) and method (2) have shallow treatment depths and are not suitable for sites with deep collapsible loess; method (3) has a large negative impact on the environment and is not suitable for existing It is used around buildings and urban areas; method (4) uses a single filler, and the compaction effect on the soil between piles is not ideal, and can only eliminate the subsidence of the foundation to a limited extent; method (5) is expensive to deal with, and is generally not accepted Adopted; method (6) when the ground around the site sinks and cracks when flooded, it is easy to cause "running water" to penetrate holes and affect the safety of surrounding buildings; method (7) deal with deep collapsible loess areas, especially in self-weight collapsible loess areas In the loess site, in order to overcome the adverse effects of negative friction, the required piles are long and the economy is poor

[0006] Among the above traditional treatment methods for collapsible loess foundations, especially for sites with deep self-weight collapsible loess, there is no economical and effective foundation treatment method that can meet the requirements of high-rise buildings (tall structures) for foundation bearing capacity and settlement , therefore, finding a new treatment method for collapsible loess foundation is a focus of attention of those skilled in the art

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