Research on the Mechanism and Response Measures of Different Types of Slope Catastrophes in a Construction Site

Abstract

Fail mechanism of slope is often affected by its cause, which determines correct and reasonable countermeasures done. Wrong cognition is an important reason of slope failure, which should be emphasized in practice. Based on a construction site with 96 hectare area, slopes of site perimeter and foundation pits of different buildings are analyzed. Using origin and different standards, slopes are classified into different types, whose failure mechanism is presented by engineering geology analysis method combined with numerical one. Different countermeasures are adopted according to the mechanism. Conclusion as following. (1) Slopes within scope of building site are classified into natural slope and artificial slope. The artificial one includes cut slope, foundation pit slope and embankment slope. Natural slope is the most stable. Stability and disturbance scope of cut slope increase with excavation depth. Foundation pit slope is a typical pit-in-pit, whose stability is the poorest. Embankment slope stability is controlled by thickness and height of refilling. (2) Failure of cut and foundation pit slopes caused by excavation often occur accident by stress and strain fields changed by unloading and lateral constraint cancelled, which causes local stress larger than material strength. Local failure expands transfixion, which causes slope overall un-stability. It is typical strength reserve safety coefficients, whose safety control is limiting the weak stratum and disturbance scope. Sliding-resistant pile in this project is required that its length is passed through coal interlayer and reached into foundation base 1–2 times pile diameter. And anchor length is longer than disturbance scope presented by shear strain contour. (3) Failure of embankment slope caused by refilling often occur incident done by filling loading lager than bearing capacity, which results in slope overall un-stability. It is typical overload safety factor, whose safety control is limiting refilling thickness less than critical one allowed by base. The one in this project is 7.7m, within the thickness clay base being safe and embankment slope being stable. These above cognitions can be referred by similar engineering.