中文摘要：

选用4个不同处理深度的灰(素)土桩对大厚度自重湿陷性黄土场地进行挤密处理,并对挤密区域以下未处理土层进行深层浸水试验,研究在该浸水条件下大厚度自重湿陷性黄土地基的湿陷变形规律、处理深度和剩余湿陷量合理控制等问题。试验结果表明:灰土和素土在处理大厚度自重湿陷性黄土地基时,两者挤密效果表现差异不大;深层浸水情况下,6~15 m深度处理区域产生的变形量均不能满足上部荷载的变形要求,且呈现三段式变形规律,先期稳定,中期缓降,后期突降;根据现场浸水试验和桩基中性点相关研究,首次提出大厚度自重湿陷性黄土地区'湿陷临界深度'的概念,并初步将其确定为20~25 m,据此可以一定程度上减小深部土层剩余湿陷量,达到减小地基处理深度的目的;建议将15~20和10~15 m分别作为大厚度自重湿陷性黄土地基乙、丙类建筑的最大处理深度。

英文摘要：

A site of self-weight collapse loess with heavy section is treated by four treating depths of lime soil(pure soil) compaction pile;and beneath the compaction reign,deep soaking test on the untreated loess is carried out in order to research the law of collapse deformation,treating depth and reasonable limit of remnant collapse of the self-weight collapse loess with heavy section in this soaking condition. The results show that,when the foundation of self-weight collapse loess with heavy section is treated with lime soil and pure soil,the compaction effects of lime soil and pure soil have little difference. In case of deep soaking,the deformation in treated region with 6-15 m depths cannot meet loess code′s demands about upper load and presents a triple-section law:stable in the first test stage,slowly decreasing in middle stage,and suddenly dropping in later stage. According to the correlated researches of field soaking tests and neutral point of pile foundation,the concept of critical collapsibility depth of self-weight collapse loess with heavy section has been proposed firstly;and the critical depth is set as 20-25 m temporarily. In this way,the remnant collapse of deep loess layer can be decreased to certain degree;and the aim to limit treating depth of loess foundation is achieved. It is suggested that 15-20 and 10-15 m can be set respectively as the maximum treating depth of class B and C building in self-weight collapse loess area with heavy section.