上海软黏土压缩特性的试验研究  

Experimental study on compressibility of Shanghai soft clays

作　　者：陈波[1] 胡云世[1] 张效忠[1] 田芳 王宝峰[1] 

机构地区：[1]衢州学院建筑工程学院,浙江衢州324000

出　　处：《工程勘察》2014年第9期23-29,共7页Geotechnical Investigation & Surveying

基　　金：衢州学院人才培养基金(BSYJ201306)

摘　　要：为研究结构性对上海软黏土压缩特性的影响,利用单向高压固结仪,对取自上海不同地点的3种软黏土的原状样及相应的重塑样进行了大量的一维主固结和次固结试验。主固结试验结果表明：结构性的存在使原状样的压缩曲线位于重塑样的上方,具有明显的结构屈服应力;结构屈服应力的大小与取样方式密切相关,现场直接切取试样的压缩曲线的结构屈服应力点最明显,应力值最大,厚壁样的压缩曲线则几乎没有屈服应力点。次固结试验结果表明：结构性的存在使原状样的次固结系数与固结压力密切相关,且次固结系数最大处的固结压力为结构屈服应力的1.5-2.5倍,而正常固结状态的重塑样的次固结系数与固结压力几乎无关。最后,正常固结状态下上海软黏土的次固结系数分布范围表明,其次压缩性为中等至高等,次固结系数与压缩指数的比值Ca/Cc表明,上海软黏土为无机质黏土及粉土。A large number of one-dimension primary and secondary consolidation tests have been carried out to study the effect of soil structure on compression characteristics on undisturbed and remolded samples obtained from three different soft clays in Shanghai.The primary compression test results show that the compression curves of undisturbed samples are above that of the remolded samples and the structure yield stress is obviously existed in the undisturbed samples.The magnitude of structure yield stress is related with the sampling method.The structural yield stress point is found in the samples taken by in-situ cut while no yield point is observed in the samples taken by thick wall method.Based on the secondary consolidation compression curves of undisturbed and remolded samples,it is found that the secondary consolidation coefficient of undisturbed samples is related with the consolidation pressure due to the soil structure and the consolidation pressure at maximum secondary consolidation coefficient is about 1.5 - 2.5times of the structure yield stress for undisturbed samples.While there is no relationship between secondary consolidation coefficient and consolidation pressure for remolded samples.The values of secondary consolidation coefficient in normal consolidation state and the values of Ca/Ccshow that the Shanghai soft clay is inorganic clay and silt with moderate to high secondary compressibility.

关 键 词：软黏土 原状样 重塑样 结构屈服应力 次固结系数 

分 类 号：TU411.3[建筑科学—岩土工程]