【作者】 曲宏略；

【导师】 张建经；

【作者基本信息】 西南交通大学 ， 岩土工程， 2013， 博士

【摘要】 由于桩板式抗滑结构具有抗滑能力强、施工安全简便、速度快、工程量小等优点,因此被广泛应用于基覆和顺层边坡的滑坡治理中,从“5.12”汶川地震支挡结构的震害调查也发现,桩板式抗滑挡土墙具备优良的抗震性能,对于此结构,目前国内外在静力设计方面已进行了一些研究,然而对抗震机理的研究较少,对桩板式抗滑挡墙的抗震性能研究更少,致使至今仍缺少成熟的抗震设计计算方法,并使得这一经济合理的工程结构在抗震领域的运用上受到了很大的限制。鉴于此,本文以汶川地震公路、铁路支挡结构的震害调查为研究背景,设计完成了2个相似比为1：10的桩板式抗滑挡土墙支护边坡模型,以归一化处理后的卧龙台站地震波作为设计输入地震波,开展了大型振动台试验,并借助数值模拟和理论分析手段对其进行了拓展,该论文的研究成果将为深入揭示桩板式抗滑挡土墙的抗震机理、完善结构工作机制研究和改善抗震设计方法提供有力的理论依据和参考。该论文取得的主要成果和结论如下：(1)大型振动台模型试验相似比设计结合地震调查情况,选取典型震害工点,进行了2个模型的大型振动台试验研究。根据模型试验的相似性要求,制定了本试验的相似关系设计基本原则,并根据量纲分析法完成了模型的相似比设计,推导了试验所涉及物理量的相似常数,确定了模型相似材料和物理力学参数,选取了台面输入加载方案。此外,对试验过程中挡土结构和边坡模型的制作进行了详细介绍,为同类试验提供了有价值的参考。(2)桩板式抗滑挡土墙加固边坡的地震响应特性利用从上述2个结构模型试验中测得的地震土压力、位移、加速度和锚索轴力的时程数据,分别进行详细、系统的分析,得出了桩板式抗滑挡土墙在不同地震动参数作用下桩身内力、结构变形、锚索轴力与剪应力的动态响应规律,并认识了加固边坡中的加速度响应特性和地震波传播规律。(3)桩板式抗滑挡土墙的数值分析利用FLAC3D有限差分法建立了结构一土一锚相互作用的三维模型,把归一化处理后的汶川卧龙波、Kobe波和E1Centro波等实测地震记录用作激励,完成了多个工况的动力时程反应计算。针对影响结构地震响应的输入地震动参数、岩土材料参数和结构设计参数分别进行了参数影响分析,得出了结构在不同参数下的地震响应规律。此外,数值分析工作也贯穿到桩板式抗滑挡土墙加固边坡的抗震机理研究和设计方法的验证等各个章节。(4)桩板式抗滑挡土墙加固边坡的抗震机理结合模型试验、数值分析和理论分析的研究成果,应用数学和力学方法,研究了地震作用下桩板式抗滑挡土墙加固边坡的变形规律,得到了加固边坡在地震下具有不同位移特性的分区特征,并从桩前后土体与结构运动不一致的角度揭示了结构一土动力耦合作用的工作机制,此外,通过MTS试验分析了锚固体系在破坏过程的不同阶段界面粘结力的变化情况和加载周期对极限承载力的影响,提出了锚固体系的位移控制原则。(5)桩板式抗滑挡土墙的抗震设计方法结合振动台试验、数值分析成果,对桩板式抗滑挡土墙的拟静力设计法提出了修正建议,考虑到锚索安装会引起桩后土体应力重分布的效果,推导了预应力锚索桩板式抗滑挡土墙的抗震设计方法。此外,鉴于地震动特性和结构本身特性对抗震性能的影响,运用Pushover能力谱法,提出了桩板式抗滑挡土墙的频谱设计方法,并提出了考虑近断层脉冲效应的R因子折减估算模型,在此基础上,结合性能设计思想,考虑了刚性桩与柔性桩抗震性能的差异性,提出了桩板式抗滑挡土墙的“三级设防”标准。上述修正建议和新的设计方法均通过振动台试验和数值分析的手段进行了验证。更多还原

【Abstract】 Due to the advantages of stablizing ability, safe, fast and simple construction, etc., the anti-sliding sheet pile retaining wall has widely applied to prevent landslide of slopes with overlaps and layers. From the investigation of retaining structure damage in the "5.12" Wenchuan earthquake, it was found that the anti-sliding sheet pile retaining wall has excellent seismic performance. However, domestic and foreign research mainly focus on static design, lack understanding of seismic mechanism, and there are few researches on seismic performance of the anti-sliding sheet pile retaining wall, therefore seismic design calculation method is not well developed. The situation restricts the application and development of the economic and reasonable structure in the field of seismic engineering. In view of this, based on the investigation of damaged retaining structures from highway and railways in the Wenchuan earthquake, large scale shaking table tests were performed, in which two structure models of anti-sliding sheet pile retaining wall for stabilizing slope were designed and completed with similitude ratio1:10, scaled acceleration time history of the Wolong station is used as an input motion. In addition, numerical simulation and theoretical analysis were used to expand the achievements. To further reveal seismic mechanism, complement structure work function and improve seismic design of anti-sliding sheet pile retaining wall, the research results propose powerful theory basis and reference. The main achievements and conclusions are summarized as follows:(1) Similitude ratio design of large scale shaking table testsBased on the situation of investigation, two typical worksites were chosen to perform large scale shaking table test. According to the model test (with similitude requirements), basic principles of similitude relationships were determined, similitude model design was completed with the method of dimension analysis, similitude constants involved in the tests were deduced, model materials and physico-mechanical parameters were confirmed, and loading program of shaking table was determined. In addition, the processes of making the modeled retaining structures and slopes were introduced in details, which will provide valuable references for the similar test.(2) Seismic response characteristics of stabilized slopes with anti-sliding sheet pile retaining wallAccording to the measured time histories of seismic earth pressure, displacement, acceleration and anchor axial force from above two structural model tests, detailed and system analysis were performed. Through the analysis, the dynamic response characteristics of internal force of the pile, deformation of the structure, and axial force and shear stress of the cable under the action of different ground motions were obtained, and acceleration response characteristics and seismic wave propagation laws in stabilized slope were known.(3) Numerical analysis of anti-sliding sheet pile retaing wallAccording to the finite difference method, the software FLAC3D was chosen, a three dimensional model with considering structure-soil-anchor interaction was established. Through normalization, acceleration time histories of the Wolong, Kobe and El Centro records were used to excite the shaking table, and the dynamic time history response calculation of multiple modes were completed. According to the main influence of seismic response to structure, the ground motion parameters of input wave, geotechnical material parameters and structure design parameters were focused on studying influence analysis of parameters respectively, seismic response characteristics with different parameters were obtained. In addition, numerical analysis is through other chapters of seismic mechanism research in stabilized slope with anti-sliding sheet pile retaining wall and validation of seismic design method.(4) Seismic mechanism of stabilized slope with anti-sliding sheet pileThrough research of model tests, numerical and theoretical analysis, with the methods of mathematics and mechanics, the deformation law of stabilized slope with sheet pile retaining wall under seismic effect was studied, the zoning characteristics with different displacements were obtained, and the structure-soil dynamic coupling mechanism was revealed focusing on the inconsistent movement of structure and soil around pile, In addition, the change characteristics of cohesive force of anchorage system in different stages of interface failure process and the influence of loading period to ultimate bearing capacity were studied through the MTS test analysis. The displacement control principle of anchorage system was put forward.(5) Seismic design method of anti-sliding sheet pile retaining wallFor sheet pile retaining wall, revised suggestions on pseudo static design was put forward through shaking table tests and numerical analysis. For prestressed anchor sheet pile retaining wall, considering the soil stress redistribution behind pile from anchor installation, a seismic design method was derived. In view of the influence of the ground motion and structural characteristics to seismic performance, the seismic design method with spectrum for sheet pile retaining wall and the R factor reduction estimation model considering near fault pulse effect were put forward, by using Pushover capacity spectrum method. Based on this, combined with performance design thought, the "three level fortification" standard for anti-sliding sheet pile retaining wall was established, which considered the differences of seismic performance from rigid pile and soft pile. The above revised suggestions and new seismic design methods were all verified through the shaking table tests and numerical analysis.更多还原