微型桩群桩支护均质土滑坡的振动台模型试验  

SHAKING MODEL TEST ON SOIL LANDSLIDE SUPPORTED WITH MICROPILES

作　　者：李楠[1] 门玉明[1] 汪班桥[1] 韩冬冬[1] 刘雪玲 LI Nan;MEN Yuming;WANG Banqiao;HAN Dongdong;LIU Xueling(School of Geology Engineering and Geomatics,Chang'an University,Xi'an 710054)

机构地区：[1]长安大学地质工程与测绘学院

出　　处：《工程地质学报》2019年第6期1371-1378,共8页Journal of Engineering Geology

基　　金：国家自然科学基金项目(41572261,41472266,41502277);中央高校基本科研业务费专项资金项目(310826175029,310826171016,300102268209)资助~~

摘　　要：为研究地震作用下微型桩群桩支护均质土滑坡的地震动力响应特性,依托大型振动台,设计完成几何相似比为8︰1(原型∶模型)的物理试验模型。试验以El Centro波、汶川波、Kobe波以及不同频率的正弦波为激励波,研究地震动力作用下微型桩群桩的破坏模式、加桩后土质滑坡的加速度响应规律等。试验结果表明:(1)地震激励后微型桩的破坏模式与静力情况类似,呈反"S"型变形,弯曲破坏范围主要分布在滑面上1. 4~4倍桩径内和滑面下1. 4~3. 4倍桩径内。(2)不同频谱特性的地震波激励时,滑坡加速度响应不同。激励频率越靠近滑坡自振频率,其加速度响应越强烈。微型桩群桩支护滑坡的加速度响应具有高程放大效应,且激励频率越靠近坡体自振频率,其高程放大效应越显著。(3)微型桩群桩支护结构对地震波有一定的阻滞作用,支护部位(尤其是坡脚)坡面的加速度响应明显弱于坡内,可限制坡表效应,但伴随坡高的增大,这种阻滞作用趋于减弱,无支护部位的上部坡体仍会出现坡表效应。This paper examines the seismic response of soil landslide supported with micropiles. It is based on tests of large-scale shaking table. A landslide model with a scale of 8︰1 is made. The El Centro wave,Wenchuna wave,Kobe wave and Sinusoidal wave are regarded as the seismic excitation. The landslide failure characteristics and acceleration response under the seismic waves were analyzed. The test results indicate the following findings.(1)The failure pattern of micropile after earthquake shows the reverse"S"-type,which is similar to that under static loads. The destruction area of micropile mainly distributes in 1. 4-4 times pile diameter above the sliding surface and 1. 4-3. 4 times pile diameter below the sliding surface.(2) Acceleration response is different under different seismic waves with different spectrum characteristics. The closer excitation frequency to the natural frequency of landslide,the stronger the dynamic response of the landslide. The acceleration response of the landslide with micropiles has obvious elevation amplification effect. The higher the excitation frequency is,the more significant the elevation effect is.(3) Micropiles can suppress seismic waves. The acceleration in landslide surface that supported by micropiles is weaker than that inside the landslide(especially the landslide toe). However,with the increase of height,it ends to weaken,consequently,the upper part without supporting structure has surface effect.

关 键 词：地震 微型桩 土质滑坡 加速度响应 破坏特征 

分 类 号：P642.22[天文地球—工程地质学]