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在中国甘肃省的黑方台阶地上从上世纪60年代开始出现人类定居和开垦活动,并自1968年发展为灌溉农业。随着灌溉的进行地面已出现沉陷和滑坡。地表沉陷是由灌溉水的充填引起黄土结构崩塌造成的。然而崩塌和湿润化对剪切特征的影响目前还不清楚。为了研究湿化后的黄土剪切特征的变化,进行了对马兰黄土未经扰动和重塑土样的直接剪切盒测试。结果显示未扰动土样的粘合力和内摩擦角在湿润化后都下降了,而所观察到的重塑土的弹度参数只有少许变化。未扰动土的不饱合粘合力,据认为其受胶结物质的影响,在饱合后消失了。经灌溉的土的不饱合强度参数与未灌溉土相比表现出差异,它们可能受土壤水分的强烈影响。
Human settlements and reclamation began in the 1960s on the Black Steps in Gansu Province and developed into irrigated agriculture since 1968. Subsidence and landslides have occurred on the ground as irrigation progresses. Surface subsidence is caused by the collapse of the loess structure caused by the filling of irrigation water. However, the impact of collapse and wetting on shear characteristics is not clear. In order to study the change of shear characteristics of loess after wetting, the direct shearing box test of Malan loess undisturbed and remolded soil samples was conducted. The results show that the adhesion and the internal friction angle of undisturbed soil samples decrease after wetting, while the observed elastic modulus parameters of the remolded soil vary only slightly. Undisturbed soil unsaturated adhesion, it is believed that by the cementitious material, disappeared after saturation. Unsaturated strength parameters of irrigated soil show differences compared to unirrigated soil, and they may be strongly influenced by soil moisture.