格构锚固边坡地震响应的振动台试验研究

设计并完成比例尺为1∶8的边坡大型振动台模型试验,研究格构锚杆框架支护边坡在汶川波水平向、竖直向和水平竖直双向激振下的动力响应特性.研究结果表明:3种激振方式都会使边坡产生水平和竖直向加速度动力响应,且呈现出明显的非线性特征.水平向激振主要产生水平向加速度放大效应,边坡上方动力响应强度比中下方动力响应强度明显,内部动力响应强度比坡面动力响应强度明显；竖直向激振主要产生竖直向加速度放大效应,边坡中上方坡内动力响应强度大于坡面动力响应强度,边坡下方坡内动力响应强度则稍弱于坡面动力响应强度；加速度动力响应峰值放大系数(PGAA)随坡高也呈显著的非线性特征:在水平向激振下,水平和竖直向PGAA都是随坡高非线性增大；在竖直向激振下,水平向PEAA和激振加速度峰值AZmax≥0.400g时的竖直向PGAA随坡高非线性增大；在水平和竖直双向激振下,边坡中下方水平向PGAA和AXmax≥0.400g时竖直向PGAA随坡高非线性增大.3种激振方式下动位移响应主要出现在水平方向上,且呈现出非线性特征.水平向或水平竖直双向激振下,主要产生水平方向的永久位移,其量值接近但方向相反；竖直向激振下产生的水平和竖直向永久位移较小.3种激振方式下主要产生水平方向动土压力响应,响应程度比较接近,呈现出非线性特征,动土压力峰值的最大值都出现在坡中.

Shaking table test study on dynamic response of slope with lattice framed anchor structure during earthquake

A slope model with the geometric scale of 1:8 was designed and a large-scale shaking table model test was performed to study the dynamic response characteristics of acceleration,displacement and earth pressure of the slope with lattice framed anchor structure during X,Z,and XZ direction excitation of Wenchuan seismic wave respectively.The results show that three excitations can make slope produce the dynamic acceleration responses along horizontal and vertical directions and the responses present obvious non-linearity.During the horizontal excitation,the acceleration amplification effect of slope appears mainly in the horizontal direction,and the response intensity of the slope upper is greater than that of the middle-lower part,and the internal slope is greater than that of slope surface.During the vertical excitation,the acceleration amplification effect of slope appears mainly at the vertical direction,the internal response intensity at the middle-upper slope is greater than slope surface,and the lower part of the slope is opposite.The peak ground acceleration amplification(PGAA) effect with the height of slope also exhibits non-linearity: during the horizontal excitation,PGAAs along X-and Z-directions increase with slope height nonlinearly;during the vertical excitation,X-PGAA and Z-PGAA at AZmax≥0.400g increase with slope height nonlinearly;during XZ excitation,X-PGAA at middle-lower part of slope and Z-PGAA at AXmax≥0.400g increase with slope height nonlinearly.During three excitations,seismic displacement response appears mainly at horizontal direction,and presents obvious non-linearity.During X-or XZ excitations,the permanent displacement of lattice frame is presented mainly at the X direction,and the two kinds of permanent displacements are equal approximately but in the opposite direction.The X-and Z-permanent displacements during the vertical excitation are small.The seismic earth pressure response at X direction is mainly presented non-linearly during three directions excitation,and the response intensity is closer.The maximum of peak seismic earth pressure is only at the middle part of slope.