静力触探技术(CPT)在砂性地基处理验收检测中的应用

Application of cone penetration test in acceptance inspection of sand foundation treatment

在砂土上进行地基处理设计时,为了满足上部结构的稳定性及使用要求,常规定一项或多项验收指标(液化判别、相对密度等)。如何判断经过处理后的地基满足验收指标是关键问题。针对上述问题,工程上常采用原位试验数据建立与验收指标的相关性,得到经验公式。对比国内外常用的基于CPT计算砂土指标的公式,综合确定验收曲线(满足最小锥尖阻力q_(c)和土层深度的关系)。结果表明:1)在满足砂土相对密度的同时,有效内摩擦角和承载力不作为控制因素。2)若工后沉降不满足要求,应适当提高基于相对密度要求的验收标准。3)CPT能提供关于土层数据的连续曲线,与土层性质之间的数据较为丰富。4)基于CPT计算的验收指标,可为地基处理工艺提供指导依据。

In order to satisfy the stability and use requirements of the superstructure,one or more acceptance indexes(liquefaction judgment,relative density,etc.)are often specified in the design of the foundation treatment on sand soil.How to judge that the treated foundation meets the acceptance index is the key problem.In view of the above problems,the correlation between the in-situ test data and the acceptance index is often established in engineering,and the empirical formula is obtained.In this paper,the acceptance curve(which satisfies the relationship between the minimum cone resistance q_(c) and the soil depth)is determined comprehensively by comparing the commonly used formulas for calculating sand indexes based on CPT at home and abroad.The results show that:1)The effective internal friction angle and bearing capacity are not considered as the controlling factors while the relative density of sand is satisfied.2)If the post-construction settlement does not meet the requirements,the acceptance criteria based on the relative density requirements should be appropriately raised.3)CPT can provide continuous curve of soil layer data,and there is abundant data between it and soil properties.4)The acceptance index based on CPT calculation can provide guidance for the foundation treatment technology.