基覆边坡动力响应的模型试验研究

Experimental Research on Dynamic Response of Bedrock and Overburden Layer Slope

竖向地震动对地震边坡稳定性有很大影响,基于此,设计了基覆边坡的模型试验(水下爆炸振动),对界面光滑无支挡结构(A坡)、界面光滑有支档结构(B坡)及界面粗糙无支挡结构(C坡)三种类型基覆边坡概化模型的破坏模式和竖向加速度响应特征进行了研究。利用加速度比这个无量纲量描述测点加速度响应的主要特征,在此基础上对比分析三种结构的基覆边坡的破坏模式、加速度响应特征和桩板墙的土压力分布。结果表明:三种边坡的表层松散土体均产生碎屑流状的下滑滚动,且C坡最明显,A,B坡沿交界面错动且在覆盖层顶部可以看到明显的下错现象;A坡动力稳定性最差,C坡最好,加固设计中应优先考虑加固滑面;爆炸试验中桩板墙上的动土压力峰值出现在1/3墙高处。

Vertical ground motion has great influence on the stability of seismic slopes. The model test for bedrock and overburden layer slope was designed （underwater explosion vibration） to study the failure mode and vertical acceleration response property of three types of bedrock and overburden layer slope generalization including the slope with smooth interface named A-Slope, the slope with retaining structure named B-Slope and the slope with rough interface named C-Slope. The acceleration ratio is dimensionless quantities description measuring point as main characteristic, on this basis, the comparison analysis on failure mode, acceleration response property, slab-pile wall soil pressure distribution of three structures of bedrock and overburden layer slope were performed. The comparison analysis indicated that the debris flow and rolling of loose soil was observed in every slope test of all three types, and it is the more obvious in the C-Slope tests. A-Slope and B-Slope were displaced along the intersection. The fracture at the top of slope can be clearly observed in the A-Slope and B-Slope tests. The dynamic stability of A-Slope was the worst one and C-Slope was the best one. Reinforcing the sliding surface should be considered firstly in seismic bedrock and overburden layer slopes. The peak value of dynamic soil pressure was observed at the third upper part of slab-pile retaining wall.