粗粒土应力诱导各向异性真三轴试验研究  

Stress-induced anisotropy of coarse-grained soil by true triaxial tests

作　　者：施维成[1,2] 朱俊高[1] 何顺宾[3] 刘汉龙[1] 

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098 [2]常州工学院土木建筑工程学院,江苏常州213002 [3]成都勘测设计研究院,四川成都610072

出　　处：《岩土工程学报》2010年第5期810-814,共5页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金委员会;二滩水电开发有限责任公司雅砻江水电开发联合基金项目(50639050);河海大学岩土力学与堤坝工程教育部重点实验室开放基金项目(GH200904);江苏省高校自然科学研究项目(09KJD560003)

摘　　要：使用河海大学最新研制成功的真三轴仪,对粗粒土进行不同主应力方向上的单向加荷试验。结果表明,在σ1、σ2、σ3方向上单向加荷时,加荷向变形都为压缩,而侧向变形较为复杂。当在σ1或者σ2方向上单向加荷时,σ3方向上都是发生膨胀,而另一个侧向(即σ2或σ1方向上)没有明显变形;当在σ3方向上单向加荷时,两个侧向(即σ1、σ2方向上)都几乎没有变形。分析认为:剪切作用增强即应力状态接近破坏面,会发生侧向膨胀;反之,剪切作用减弱,则无侧向膨胀产生或侧向膨胀较小。对σ3方向单向加荷的情况研究表明,该应力路径下,p、q、b这3个量的变化都是使试样的应力状态远离破坏面,剪切作用减弱,因此侧向膨胀很小或没有。所试验的粗粒土在一般应力条件下各向异性性质显著。Using the true triaxial apparatus recently developed in Hohai University,a series of unilateral loading tests are performed on coarse-grained soil,in which two of the three principal stresses are invariable,and only one increases.The experimental results show that the deformation in the loading direction is compression in all cases,while the deformations in the other two lateral directions are complicated.When loading is applied in the direction of the major or the intermediate principal stress,the deformation in the lateral direction of the minor principal stress is dilatancy and few deformation occurs in the other lateral direction which is the corresponding direction of the intermediate or major principal stress;when loading is applied in the direction of the minor principal stress,the dilatant deformation occurring in the direction of either the major or the intermediate principal stress is very little.It is indicated that the dilatant deformation is mainly caused by the increment of the shear effect.That is to say： if the shear effect increases,the dilatant deformation will occur;if the shear effect decreases,there will be little dilatant deformation.The instance with loading applied in the direction of the minor principal stress is studied.It is found that the variations of p,q,b all make the stress state away from failure surface,consequently the shear effect decreases and little dilatant deformation occurs.The tested soil exhibits strong anisotropy in general stress states.

关 键 词：各向异性 粗粒土 真三轴试验 单向加荷 侧向变形 

分 类 号：TU411[建筑科学—岩土工程] TV641[建筑科学—土工工程]