软土地基上堤防稳定性研究  

PRELIMINARY STUDY OF STABILITY OF LEVEE ON SOFT GROUND

作　　者：徐光明[1] 高长胜[1] 张凌[1] 杨守华[1] 

机构地区：[1]南京水利科学研究院土工研究所,江苏南京210024

出　　处：《岩石力学与工程学报》2005年第13期2315-2321,共7页Chinese Journal of Rock Mechanics and Engineering

摘　　要：完成了2组土工离心模型试验,分别研究了淮河入海水道软土段堤防在竣工期和水位骤降期的稳定性及其破坏机理。由于无法从原型取到大尺寸具有代表性的原状土试样,因此,将取自原型地基土层和堤身土体的扰动土样重塑后制备成软基和堤身,并控制其不排水剪强度与原型一致。为了测定原型堤防的稳定安全系数,对模型堤防进行了破坏性试验,即让模型承受超出设计加速度水平的离心力作用,直至出现明显的失稳滑动迹象,由此测得软基上堤防的极限高度,同时根据堤防剖面位移矢量确定滑弧所在位置。试验结果表明,在竣工期软基上堤防的破坏为滑弧穿过软土层的深层滑动,而在水位骤降期,破坏面在堤防堤身中形成,随后向深处发展。由此可知,软土地基上堤防稳定性主要为软土层的承载能力所控制,同时在一定程度上也受到水位骤降的影响。鉴于原型堤基天然软土存在结构性,建议在今后的离心模型试验中能够考虑这种结构性的相似问题及其模拟途径。Muddy clay from the soft ground of Huaihe River's levees for a flood channel to sea was retrieved and remolded to investigate the mechanism of stability of levees on soft ground after the end of construction and during rapid drawdown of water level, respectively, by centrifugal model tests. The safety factor against sliding was analyzed on the basis of slope surface displacement development while the location of slip was determined from the vector diagram of displacement on slope cross-section. It is observed from the overloading tests, by accelerating models over the predetermined g-level, that the sliding surface of the levee on soft foundation is deep seated one, which passes through the soft ground, after the completion of construction, whereas there is a failure surface, which passes through the toe of the slope but occurred earlier than the deep seated one, during rapid drawdown of water level. These test results show that the stability of the levee on soft ground is mainly governed by the bearing capacity of the soft soil layer and be influenced, to a certain degree, by action due to rapid drawdown of water level. Suggestion on more realistically modeling for stability behavior of levee on natural soft ground is also proposed on the basis of similitude consideration of inherent structure of in-situ clay.

关 键 词：土力学 软土地基 堤防 稳定安全系数 竣工期 水位骤降期 离心模型试验 

分 类 号：TU471.8[建筑科学—结构工程]