有机质污染红黏土地基加固效果的力学效应分析

STUDY ON MECHANICAL EFFECT OF RED CLAY POLLUTED BY ORGANIC MATTER DURING STRENGTHENING FOUNDATION

某工程场地水泥搅拌桩桩体质量抽芯检测中,发现某些桩体的质量存在问题。现场开挖检查,发现"问题桩"呈带状分布。通过对场地的进一步勘查,得知该场地局部地段由于化粪池处理不当,造成红黏土被有机质污染,导致水泥搅拌桩加固的红黏土地基的桩体质量出现问题。通过选取代表性的土样进行室内有机质污染红黏土相关指标的测试,并对勘察资料及室内试验资料的统计、分析,得到该场地有机质污染红黏土的物理力学性质指标。结合现场抽芯和开挖观察以及对微观结构的分析,探讨有机质污染红黏土对水泥搅拌桩力学效应的影响。研究表明:该场地红黏土被有机质污染的程度,随着距化粪池的渐远而减弱,红黏土的物理力学性质指标变幅的程度逐渐减小,力学软化效应的显著性依次减弱,致使"问题桩"呈带状分布。

Lots of ＂problematical piles＂ were discovered during inspection of loose core to cement mixing piles, and the piles were in zonal distribution through inspection of excavation. Emergence of the problematical piles was that the red clay was polluted. In this paper, a series of tests of physical and mechanical properties were done by choosing a representative red clay sample of cement mixing piles being polluted in the reinforcement areas. Combining inspection of loose core and excavation, it was discussed influences of the red clay polluted by organic matter on the mechanical property of the cement mixing piles. The research indicates that mechanical softening effects were gradually weakend and the decrease of the indexes of physical and mechanical properties were decreased with the decrease of the distance between cement mixing piles and septic tank. As a result, the problematical piles were in zonal distribution.