摘要
在兰新铁路第二双线一处典型泥岩地基工点处,采用开挖不同深度浸水孔并施加上部荷载方法,进行3个试验基坑的泥岩地基原位浸水膨胀变形试验,分别研究在9.75,21.44,38.99,58.48,65.31,77.99 k Pa六种上覆荷载情况下,以及0.7,1.1,1.5 m三种浸水深度情况下,泥岩地基的膨胀变形特性。结果表明:泥岩浸水膨胀变形表现为短暂软化沉降、膨胀骤增、膨胀减缓、膨胀平衡稳定4个阶段;得出不同浸水深度与膨胀变形值为非线性关系;在浸水孔深度1.5 m,上部荷载9.75 k Pa时,地基最大膨胀量约41 mm;在上覆荷载值一定的情况下,浸水后地基泥岩含水率会达到最大限值,约14%,且浸水量不会随着外界水分补给而增大;当泥岩内部含水率在限值范围内增大时,会储存有膨胀能,在上覆荷载减小或浸水深度增大的情况下,泥岩地基以稍滞后的膨胀变形体现出其膨胀能;拟合得出泥岩地基膨胀量与上覆荷载的非线性关系曲线及关系式;总结泥岩加荷–浸水膨胀以塑性变形为主,卸载情况下泥岩的回弹量值占总变形量的6.39%~7.00%。
The deformation of mudstone foundation under the second line of Lanzhou to Xinjiang Railway was studied with in-situ tests. Overloadings of six levels such as 9.75,21.44,38.99,58.48,65.31 and 77.99 k Pa were applied to three pits and the corresponding expansions with the water soaking depths of 0.7,1.1 and 1.5 m respectively were measured. The process of mudstone expansion due to water soaking was found to have four stages:brief softening and subsidence,surging expansion,slow expansion and stable expansion. A nonlinear relationships between the water socking depths and soil expansion was obtained. When the water soaking depth was 1.5 m and the over load was 9.75 k Pa,the largest soil expansion value was 41 mm. The maximum moisture content of mudstone was about 14% and would not increase with water recharging. When the moisture content of mudstone was increased around a range of values,with a bit of a lag,the expansion deformation of mudstone foundation was showed by inner accumulated energy. The relationship between the over load and expansion deformation was obtained. The deformation was mainly plastic and the rebounding value due to unloading was 6.39%–7.00% of the total deformation.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2015年第8期1684-1691,共8页
Chinese Journal of Rock Mechanics and Engineering
基金
长江学者和创新团队发展计划(IRT1139)
甘肃省基础研究创新群体资助(145RJIA332)
兰州交通大学青年科学基金(2012028)
关键词
基础工程
客运专线
泥岩
原位试验
膨胀变形
膨胀阶段
卸载
foundation engineering
passenger railway line
mudstone
in-situ test
expansion deformation
expansion stages
unloading
