Research on moisture content characteristics of unsaturated sandy slope failure forms under different rainfall intensities
In order to study the internal moisture content characteristics of unsaturated sandy soil slopes under different rainfall intensities and explore the relationship between failure moisture content and failure forms and the soil-water interaction mechanism of slope failure,the change laws of the internal water content of coarse sand and fine sand slopes under different rainfall intensities and the influence of the previous rainfall on slope failure are studied through laboratory model tests.The internal mechanism of the rainfall-induced slope failure is analyzed based on soil-water characteristic curve.The test results show that there are three stages of moisture content change in the process of rainfall.In stage I,the moisture content increases approximately linearly.In stage Ⅱ,the growth of moisture content tends to be gentle.In stage m,under high rainfall intensity,the moisture content of slope body increases rapidly before slope failure.Under different rainfall intensities,the failure forms of the slope are different,and the failure moisture contents are also different.When the slope toe loss occurs,the failure moisture content is about 12％.When the slope slides in layers,the failure moisture content is 13％～18％.When the overall flow-slip occurs in the slope,the failure moisture content is about 20％.No matter what kind of damage occurs,the slope does not reach the saturation state.Different initial moisture content also affects the failure form and failure time of the slope.The higher the initial water content,the larger the failure scale of slope and the less time required for failure.As the moisture content of the slope increases,the matrix suction of the slope decreases,the shear strength decreases,the sliding force is greater than the anti-sliding force,and the slope eventually fails.
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