玉树机场公路堆积层滑坡支挡结构的地震响应试验研究

发布时间：2018-02-20 04:36

本文关键词： 堆积层地震滑坡支挡结构地震响应特征　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：“4.14”玉树地震引发了G214线玉树机场公路段堆积层斜坡发生滑坡,并且形成了0“、1#和2#三个主要滑坡群,滑坡造成公路沿线部分既有抗滑支挡结构发生不同程度的破坏,为了保证机场公路畅通,亟需对3个滑坡群进行工程治理。由于滑坡发生在较为松散堆积层斜坡上,滑体疏松,很难确定不同抗滑支挡结构在地震再次发生时所受力的大小、分布形式以及它们的动态变化情况,这是玉树机场公路滑坡整治工程设计中需要解决的问题。本文结合青海省交通建设科技项目“青海玉树地震滑坡(公路)与边坡灾害防治技术研究”(N0：2010-03),以玉树G214线玉树机场段0#滑坡群第4块滑坡作为典型工点进行研究,设计完成了4组(多排抗滑桩动力响应试验、桩顶约束型抗滑桩动力响应试验、多锚点预应力锚索桩板墙动力响应试验和集束式桩锚结构)相似比为1：75的滑坡——抗滑支挡结构模型,开展了大型振动台模型试验,研究堆积体滑坡支挡结构的地震动态响应特征以及抗滑支挡效果,为玉树机场公路堆积层滑坡抗滑支挡结构设计提供理论指导。主要结论如下：1.多排抗滑桩、桩顶约束型抗滑桩以及多锚点预应力锚索桩板墙中抗滑桩所受地震动土压力与残余土压力桩后分布形式相似,均呈现“R”型分布,受荷段最大土压力位置为滑面以上约1/3处,锚固段最大土压力位置靠近桩底部；桩前分布形式相似,最大土压力位置为滑面处。当土体发生塑性破坏时,受荷段最大土压力位置上升至滑面以上约2/3处,而锚固段最大土压力位置基本不变。2.设置锚索改变了抗滑桩的受力状态使桩对土体产生了反向作用,导致桩体悬臂段土压力增长幅度更为均匀,土压力值更加接近。预应力锚索在地震荷载作用下的变化受输入地震动曲线影响,应变幅值随PGA的增大呈现“增大-减小-增大”的变化情况,出现预应力损失,所以应注意锚索的安全储备；9度甚至更高烈度情况下其桩顶位移变化小,锚索限位作用明显。3.输入地震波加速度是模型地震响应特征的主要影响因素,支挡结构的动土压力、残余土压力、位移、应变、加速度放大系数及其其这些特征的变化速率等均受输入地震波加速度影响,而且均与输入地震波加速PGA呈正增长关系；模型响应特征在XZ双向地震荷载作用下要较X单向地震荷载作用明显,说明竖向地震荷载增强整体地震效应。4.试验表明堆积层滑坡中各种支挡结构模型经过地震工况作用下,抗滑支挡效果不尽相同：组合支挡结构(预应力锚索框架结构+微型桩)多锚点预应力锚索桩板式抗滑结构单锚点预应力锚索桩板式抗滑结构桩顶约束型抗滑桩支挡结构普通抗滑桩支挡结构；对于抗滑支挡结构的布置形式而言,多排支挡结构在地震荷载作用下的抗滑支挡效果要好于单排抗滑支挡结构。
[Abstract]:The "4.14" Yushu earthquake caused the slope of the accumulation layer of Yushu Airport Section of Line G214 to landslide, and formed three main landslide groups, namely "0" and "2#". The landslide caused the damage of some existing anti-slide retaining structures along the highway to varying degrees. In order to ensure the smooth running of the airport highway, it is urgent to carry out engineering treatment for the three landslide groups. Because the landslide occurs on the slope of the relatively loose accumulation layer and the sliding body is loose, it is difficult to determine the magnitude of the force exerted by the different anti-slide retaining structures when the earthquake occurs again. The form of distribution and their dynamic changes, This is the problem that needs to be solved in the design of highway landslide regulation project of Yushu Airport. This paper combines Qinghai Province traffic construction science and technology project "Qinghai Yushu earthquake landslide (Highway) and Slope disaster Prevention Technology Research" N0: 2010-030, Yushu G214 Line. The fourth block landslide of 0# landslide group in Yushu Airport is studied as a typical site. Four groups (multi-row anti-slide pile dynamic response test, pile top constrained anti-slide pile dynamic response test) were designed and completed. The dynamic response test of prestressed anchor cable pile and slab wall with multiple anchors and cluster pile-anchor structure with similarity ratio of 1: 75 are carried out on a large shaking table model. This paper studies the seismic dynamic response characteristics and anti-slide retaining effect of landslide retaining structure of accumulation body, which provides theoretical guidance for the design of landslide anti-slide retaining structure in Yushu airport highway. The main conclusions are as follows: 1. Multi-row anti-slide piles, The seismic dynamic earth pressure of anti-slide pile in pile top restrained pile and multi-anchor prestressed anchor cable pile and plate wall is similar to that of residual earth pressure pile, and all of them show "R" type distribution, and the maximum earth pressure position of the bearing section is about 1/3 places above the sliding surface. The position of the maximum earth pressure in the anchoring section is near the bottom of the pile, the distribution of the maximum earth pressure in front of the pile is similar, and the maximum earth pressure is located on the sliding surface. When plastic failure occurs in the soil, the maximum earth pressure position of the loaded section rises to about 2/3 above the sliding surface. However, the maximum earth pressure position of the anchoring section is basically unchanged. 2. The anchoring cable changes the stress state of the anti-slide pile and causes the pile to have a reverse effect on the soil mass, which results in a more uniform increase of the earth pressure in the cantilever section of the pile body. The variation of prestressed anchor cable under earthquake load is affected by the input seismic curve, and the strain amplitude changes with the increase of PGA, and the prestress loss occurs. Therefore, it should be noted that under the condition of safe reserve of anchor cable with 9 degree or higher intensity, the displacement of pile top is small, and the effect of anchor cable limit is obvious .3.Input seismic wave acceleration is the main influencing factor of the seismic response characteristics of the model, and the dynamic earth pressure of retaining structure. The residual earth pressure, displacement, strain, acceleration magnification factor and the change rate of these characteristics are all affected by the acceleration of the input seismic wave, and all of them are positively related to the acceleration of the PGA of the input seismic wave. The response characteristics of the model under the action of XZ bidirectional earthquake load are more obvious than that of X unidirectional seismic load, which indicates that the vertical seismic load enhances the overall seismic effect .4.The test results show that the various retaining structure models in the accumulation layer landslide are subjected to earthquake working conditions. The effect of anti-slide support is not the same: composite support structure (prestressed anchor cable frame structure miniature pile) multi-anchor point prestressed anchor cable pile plate type anti-slide structure single anchor point prestressed anchor cable pile plate type anti-slide pile pile top restraint pile. Support structure ordinary anti-slide pile retaining structure; For the arrangement of anti-slide retaining structure, the anti-slide retaining effect of multi-row supporting structure under earthquake load is better than that of single-row anti-slide retaining structure.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V35;U418.55

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