膨胀土的强度及其测试方法

发布时间：2018-11-25 12:45

【摘要】：膨胀土的强度参数是膨胀土边坡稳定分析的基础。膨胀土的特殊性以及膨胀土边坡失稳机理的复杂性使得膨胀土强度指标的获取和取值十分困难。以往对于膨胀土的强度曾开展过大量的研究工作,但无论是研究体系,还是试验方法以及强度取值原则都存在一定的差异。人们关注到膨胀土裂隙的存在,却又难以实测到裂隙面上真实的强度指标;关注到膨胀土的非饱和特性,并试图用含水率变化引起的强度衰减来解释边坡的失稳机理;然而,无论采用何种理论,都难以将膨胀土的强度与边坡的失稳机理有机的联系在一起,造成在实际工程中数值分析与边坡实际稳定状态不符的现象。仅从强度理论上讲,膨胀土仍然是一种黏性土,仍然应符合莫尔库仑强度准则。所不同的是,由于裂隙的存在,使得膨胀土的强度时而显示出均匀介质的特性,时而显示出非均匀介质的特性。因此,研究膨胀土的强度特性,不可避免的要研究裂隙以及裂隙对强度的影响问题。在大量现场工作和室内试验研究的基础上,重点探讨了裂隙对膨胀土强度的影响,提出对于膨胀土的强度应以土块强度和裂隙面强度两套指标进行描述,而土块强度又应区分为有胀缩裂隙和无胀缩裂隙两类,并进一步提出了不同强度的测试方法。
[Abstract]:The strength parameter of expansive soil is the foundation of stability analysis of expansive soil slope. Because of the particularity of expansive soil and the complexity of instability mechanism of expansive soil slope, it is very difficult to obtain the strength index of expansive soil. A lot of research work has been done on the strength of expansive soil in the past, but there are some differences in the research system, the test method and the principle of strength value. People pay attention to the existence of fissures in expansive soil, but it is difficult to measure the true strength index on the fracture surface, pay attention to the unsaturated characteristics of expansive soil, and try to explain the mechanism of slope instability by the strength attenuation caused by the change of water content. However, no matter what theory is adopted, it is difficult to combine the strength of expansive soil with the instability mechanism of slope, resulting in the phenomenon that numerical analysis does not accord with the actual stability of slope in practical engineering. In terms of strength theory, expansive soil is still a kind of clay and should still conform to the Mohr Coulomb criterion. The difference is that because of the existence of cracks the strength of expansive soil sometimes shows the characteristics of homogeneous medium and sometimes the characteristic of non-uniform medium. Therefore, in order to study the strength characteristics of expansive soil, it is inevitable to study the influence of fissures and fissures on strength. On the basis of a large number of field work and laboratory tests, the influence of fissures on the strength of expansive soil is discussed, and it is proposed that the strength of expansive soil should be described by two sets of indexes: the strength of soil block and the strength of fracture surface. The strength of the soil should be divided into two types: the dilatation crack and the non-dilatation crack, and the testing methods of different strength are put forward.
【作者单位】：长江科学院水利部岩土力学与工程重点实验室;
【基金】：国家“十一五”科技支撑计划课题(2006BAB04A10);国家“十二五”科技支撑计划项目(编号2011BAB10B05) 国家自然科学基金项目(51279015)
【分类号】：TU443

【参考文献】