Method for treating collapsible loess foundation using acid-adding presoaking method

Abstract

The present invention discloses a method for treating a collapsible loess foundation using an acid-adding presoaking method. The method comprises a first step of sampling, which refers to using a soil sampler to cut to obtain a soil sample from a collapsible loess foundation to be treated; a second step of soil sample testing; a third step of determination of the concentration of a soaking liquid; a fourth step of determination of the usage amount of the soaking liquid; a fifth step of preparation of the soaking liquid according to the determined concentration and usage amount, the soaking liquid being an acid-added aqueous solution and being an acid solution formed by uniformly mixing water with acid; a sixth step of acid-adding presoaking treatment of the collapsible loess foundation, which refers to continuously adding the soaking liquid into the collapsible loess foundation to be treated, the adding time being 3-15 days; and a seventh step of drainage consolidation, which refers to carrying out drainage consolidation treatment on the collapsible loess foundation to be treated by using a drainage consolidation method. The method provided by the invention is simple in step, reasonable in design, convenient to construct, and excellent in using effect; and by using the method, a treatment process of the collapsible loess foundation can be easily, conveniently and rapidly completed, loess collapsibility can be effectively eliminated, the strength of the loess can be effectively enhanced, and the bearing capacity of the foundation can be raised.

Description

technical field [0001] The invention belongs to the technical field of foundation treatment, and in particular relates to a method for treating collapsible loess foundation by adding acid and presoaking water. Background technique [0002] As the fourth season sediment, loess has a wide distribution area in the world, accounting for about one tenth of the land area. China is the country with the widest distribution and thickness of loess in the world. It is mainly distributed in the Loess Plateau and Northwest China. The North China Plain and the southern part of Northeast China cover an area of ​​631,000 square kilometers, accounting for about 6% of the country's land. Loess has its special internal material composition, structural characteristics and external form, which makes it different from other sediments of the same period, that is, collapsibility. This property of loess often causes catastrophes, which bring damage to geotechnical engineering built on such loess, s...

AI Technical Summary

Problems solved by technology

[0005] First, the scope of application is narrow: "Code for Buildings in Collapsible Loess Areas" GB50025-2004 points out that the traditional pre-soaking method is generally only suitable for dealing with collapsible soil layers with a thickness greater than 10m and a self-weight collapsibility equal to or greater than 50cm. For collapsible loess sites, when dealing with collapsible loess with a collapsible soil layer thickness of less than 10m or a self-weight collapsible amount of less than 50cm, it is considered that the treatment effect of the traditional pre-soaking method is not good, and the gain outweighs the gain; while for non-self-weight collapsible loess Natural loess, the traditional pre-soaking method is not available;

[0006] Second, the upper soil layer cannot be effectively treated: "Code for Buildings in Collapsible Loess Areas" GB50025-2004 points out that the traditional pre-soaking method is used to treat the collapsible soil layer with a thickness greater than 10m and a self-weight collapsibility equal to or greater than 50cm For the self-weight collapsible loess site, this method cannot completely eliminate the collapsibility of the soil layer with a depth of more than 6m, and this part of the soil layer often needs to be dealt with in combination with dynamic compaction or soil cushion replacement;

[0007] Third, high cost and long construction period: the traditional pre-soaking method consumes a lot of water and has a long construction period. Generally, it should be carried out at least half a year to one year earlier than the official project; therefore, it often results in waste of water resources and an increase in project costs;

[0008] Fourth, the treatment effect is single: the traditional pre-soaking method only eliminates the collapsibility of the self-weight collapsible loess in advance, but the strength of the loess cannot be enhanced;

[0009] Fifth, the treatment effect is poor: the common presoaking method has not taken any measures to further improve the construction effect during the consolidation drainage period when the water injection is stopped

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