独立式石箍窑洞加固模型振动台试验研究

Shaking table tests for independent stone hoop cave reinforcement model

应用配筋砂浆带等加固技术对一缩尺比例为1/4的独立式石箍窑洞震损模型进行加固,并对其进行模拟地震振动台试验,以研究独立式石箍窑洞加固模型的动力响应与抗震性能。通过白噪声扫频得到该模型各阶段的自振频率和阻尼比等动力特性,并研究了模型结构的破坏特征、动力响应及其滞回耗能。试验研究结果表明:随着输入地震动峰值加速度的增加,模型结构的自振频率和刚度下降,阻尼比增大,加速度放大系数呈下降趋势;在水平X向(面阔方向)地震作用下,窑脸侧拱顶的加速度响应大于背墙侧拱顶,中孔拱顶的加速度响应大于边孔拱顶的,中拱拱脚的相对位移值始终大于边拱拱脚,甚至大于边拱拱顶;在峰值加速度为1.00g的地震激励后,窑顶、拱顶和拱脚的X向最大侧移角分别达到了1/29、1/229和1/201。模型虽局部破坏明显,但仍未出现整体倒塌趋势,表明本文提出的方法对独立式石箍窑洞的加固效果显著。

Here, to study dynamic response and aseismic performance of independent stone hoop cave reinforcement model, a 1/4 scale model of independent stone hoop cave was strengthened by using reinforcement technology, such as, reinforced mortar belt, and shaking table tests were conducted on the model as its simulated seismic tests. Dynamic characteristics of each stage of the model, such as, natural frequency and damping ratio were obtained with white noise sweeping frequency. Failure characteristics, dynamic response and hysteretic energy dissipation of the model structure were studied. The test results showed that with increase in peak acceleration of input ground motion, natural frequency and stiffness of the model structure decrease, its damping ratio increases, and its acceleration amplifying coefficient decreases;under seismic action in horizontal X-direction, i.e., cave face width direction, acceleration response of cave face side dome is larger than that of back wall side dome, acceleration response of middle hole vault is larger than that of side hole vault, and relative displacement value of middle arch foot is always larger than that of side arch foot, even larger than that of side arch vault;after seismic excitation action with peak acceleration of 1.00g, the maximum X-direction side-shift angles of cave top, arch crown and arch foot reach 1/29, 1/229 and 1/201, respectively;although local damage of the model is obvious, there is no overall collapse trend, so the proposed method has a significant effect on reinforcement of independent stone hoop cave.