干密度对弱膨胀土的多次固结-回弹的影响  

Research on effect of dry density on multiple consolidation-rebound deformation of weak expansive soil

作　　者：薛小杰 宋星 吕鹏 XUE Xiaojie;SONG Xing;L Peng(Sun Yat sen University Sun Yat sen Memorial Hospital ShenZhen Shantou Central Hospital,Shanwei 516600,Guangdong,China;815 Geological Team of East China Metallurgical Bureau of Geology and Exploration,Hefei 230000,Anhui,China;Sun Yat sen Memorial Hospital of Sun Yat sen University,GuangZhou 510000,Guangdong,China)

机构地区：[1]中山大学孙逸仙纪念医院深汕中心医院,广东汕尾51600 [2]华东冶金地质勘查局八一五地质队,安徽合肥230000 [3]中山大学孙逸仙纪念医院,广东广州510000

出　　处：《工程建设》2023年第11期1-5,11,共6页Engineering Construction

基　　金：国家自然科学基金资助项目(41272358);广西研究生教育创新计划项目(YCSW2019161)。

摘　　要：为探究拆除重建过程中地基变形特性,本文对不同干密度(1.3、1.5、1.7 g/cm^(3))膨胀土试样在多次加卸载条件下的固结-回弹特性进行研究。结果表明:1)试样固结变形主要发生在竖向荷载为800 kPa之前,之后试样变形缓慢并趋于稳定;2)卸载时的试样回弹变形主要发生在荷载小于400 kPa阶段,400~3200 kPa阶段回弹变形平缓;3)干密度越大,试样固结作用下的变形量越小,卸载回弹后残留不可恢复变形也越小;4)试样总孔隙量是影响固结变形的主要因素,回弹过程中土颗粒的咬合作用一定程度上限制了回弹变形。本文研究成果可为膨胀土地区拆除重建工程中的地基变形控制提供一定的理论参考。In order to explore the deformation characteristics of foundation during demolition and reconstruction,the consolidation-rebound characteristics of expansive soil samples with different dry densities(1.3,1.5,1.7 g/cm^(3))under multiple loading and unloading conditions are researched.The results show that:1)The consolidation deformation of the specimen mainly occurs before the vertical load is 800 kPa,and then the specimen deforms slowly and becomes stable;2)The rebound deformation of the specimen during unloading mainly occurs when the load is less than 400 kPa.The rebound deformation is gentle in the 400~3200 kPa;3)The greater the dry density,the smaller the deformation under the consolidation effect of the specimen,and the smaller the residual unrecoverable deformation after unloading and rebound;4)The total porosity of the specimen is the main factor affecting the consolidation deformation,and the inter locking of soil particles during the rebound process limits the rebound deformation to a certain extent.The results can provide a certain theoretical reference for deformation control of foundation in the demolition and reconstruction of expansive soil area.

关 键 词：膨胀土 固结-回弹 回弹变形 地基变形 

分 类 号：TU411.5[建筑科学—岩土工程]