基于原位监测和模型试验的膨胀土高边坡稳定性分析

Stability analysis of high expansive soil slopes based on in-situ monitoring and model tests

以某25 m高的膨胀土临时渠道边坡为研究对象,通过已滑渠坡的现场探槽试验,发现渠道左右岸在高程140~142 m均赋存长大裂隙,为裂隙强度控制下的边坡失稳;针对滑裂面的位置和形态,选取有代表性的渠段开展了预应力伞型锚加固方案设计,并布置了以锚力和变形为主要监测手段的完整监测断面。针对现有土质边坡锚力监测存在的精度不高等问题,开展了室内物理模型试验,研究预应力伞型锚监测土质边坡的适用性。根据原位监测和模型试验成果,分析了渠坡在开挖、加固及降雨等过程中的稳定状态,明确了影响渠坡稳定的关键因素及渠坡加固方案的合理性,并提出了基于锚力监测的膨胀土高边坡稳定状态判别标准。

Taking a 25 m-high expansive soil temporary channel slope as the research object,through the field channel tests on sliding channel slope,long and large cracks are found at the left and right banks of the channel in the elevation between 140~142 m,and the slope instability is under the control of crack strength.According to the position and shape of the slip surface,a representative channel section is selected to carry out the design of the prestressed umbrella anchor reinforcement scheme,and a complete monitoring section with anchor force and deformation as the main monitoring means is arranged.Aiming at the low accuracy of the existing soil slope anchor force monitoring,an indoor physical model test is carried out to study the applicability of the prestressed umbrella anchors for soil slope monitoring.According to the results of the in-situ monitoring and model tests,the stable states of the canal slope during the processes of excavation,reinforcement and rainfall are analyzed.The key factors affecting the stability of the canal slope and the rationality of the canal slope reinforcement scheme are clarified.The criterion for stability state judgment of high expansive soil slopes are put forward based on the anchor force monitoring.