Method for detecting strength of soil-cement admixture by using hardness test

Abstract

The invention provides a method for detecting the strength of a soil-cement admixture by using a hardness test. The method comprises the following steps: acquiring soil samples from a variety of soil layers within on-site construction depth; carrying out sample preparation on the on-site soil samples and cement and then carrying out a hardness test and a lateral confinement-free compressive strength indoor test; collating hardness values of soil cement test pieces obtained in the test and corresponding lateral confinement-free compressive strength values and drafting a graph of relation; subjecting the graph of relation to linear-regression analysis to obtain a relation between the hardness values of soil cement at the construction site and natural logarithm values of confinement-free compressive strength; during reinforcing and maintenance of on-site construction soil cement, digging out the surface of a few reinforcing sections to expose the soil cement, testing hardness of the soil cement with a Shore durometer and calculating a confinement-free compressive strength value by directly using the linear regression relation obtained through the tests. According to the invention, destroy of reinforced soil and delay of a construction period caused by boring and sampling of the reinforced soil after reinforcement construction are avoided, and the method is concise, economic, effective and fast.

Description

technical field [0001] The invention relates to a method in the technical field of construction engineering, in particular to a method for detecting the strength of cement mixed soil with a hardness test. Background technique [0002] As the economy in the Yangtze River Delta continues to grow, the pace of urban construction is getting faster and faster. However, because coastal cities are often weak soil layers with high water content, the foundation soil often needs to be treated first when urban construction is carried out in these places. Commonly used foundation treatment methods include cement-soil mixing method, rotary spraying method, and grouting method. The above method is to use cement and other materials as a curing agent to mix cement and soft soil to form a hard cement-mixed soil (hereinafter referred to as cement-soil), which works together with the original strata to form a composite foundation to achieve the purpose of foundation reinforcement. In engineer...

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Problems solved by technology

[0005] The key steps of the standardized detection method are carried out after the cement-soil construction, which will greatly delay the construction period; and the on-site detection method of the quality of the deep cement mixture based on the mixing uniformity has the following problems: the critical value of the pH value affecting the strength of the mixed soil is selected as 10 is inconsistent with the actual situation; the influence of pH value distribution in different intervals on the strength of cement mixture is not considered, which makes the strength accuracy of the determined cement mixture poor

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