上海地区饱和粉土层中土钉墙支护的工程实践

通过虹祺花苑复合式土钉墙工程实例,阐述饱和粉土层中的土钉墙支护计算原理及现场施工要点,并总结了技术要点及注意事项以资推广。     

土钉墙与压密注浆在复杂地质条件下基坑中的应用

通过上海长途客运公司恒丰路高速客运站基坑土钉支护工程实例,阐明了土钉支护在复杂地质条件下的适用性及灵活性,并提出了相应处理措施,说明了只有有效地结合其他多种施工方法,才能更好地处理复杂情况。     

福州平安大厦深基坑支护设计与施工

深基坑支护设计与施工是当前城市高层、超高层建筑突显的技术难题。通过工程实例,从设计方案的选择到施工、监测,提供了有益的经验。     

考虑桩顶冠梁效应的水泥土挡墙变形计算方法

以ｍ法为基础,建立了考虑桩顶冠梁效应的挡墙变形计算模型,给出了计算公式。工程实例表明：该方法预测挡墙变形是可行的。     

挡土结构古典内力计算方法的讨论

根据软土地区大量基坑支护的经验,对目前挡土结构古典内力计算常用的平衡法（悬臂结构）、等值梁法（单支撑结构）和弹性抗力法的计算结果进行了分析与比较,指出了古典内力计算方法的适用性。     

海啸作用下滨水挡土墙抗震转动稳定性上限分析

地震诱发的海啸对沿海围护结构的破坏具有强度大的特点。滨水挡土墙作为重要的围护结构,海啸与地震的联合作用极易造成其发生绕墙踵的被动破坏。采用条分法,将土楔体分割成无数平行于破裂面的刚性土条,并建立绕墙踵转动的挡墙与刚性土条之间的速度容许场。基于极限上限理论,依据外力做功功率等于其内能耗散功率,推导了地震加速度系数的表达式。与经典极限平衡理论相比,该方法考虑了挡墙的位移模式,且无需假设地震土压力的作用位置。分析了浪高与海平面高度之比,内摩擦角φ及墙土摩擦角δ对滨水挡土墙稳定性的影响。     

Analytical and empirical models for predicting the drift capacity of modern unreinforced masonry walls

Displacement‐based seismic assessment of buildings containing unreinforced masonry (URM) walls requires as input, among others, estimates of the in‐plane drift capacity at the considered limit states. Current codes assess the drift capacity of URM walls by means of empirical models with most codes relating the drift capacity to the failure mode and wall slenderness. Comparisons with experimental results show that such relationships result in large scatter and usually do not provide satisfactory predictions. The objective of this paper is to determine trends in drift capacities of modern URM walls from 61 experimental tests and to investigate whether analytical models could lead to more reliable estimates of the displacement capacity than the currently used empirical models. A recently developed analytical model for the prediction of the ultimate drift capacity for both shear and flexure controlled URM walls is introduced and simplified into an equation that is suitable for code implementation. The approach follows the idea of plastic hinge models for reinforced concrete or steel structures. It explicitly considers the influence of crushing due to flexural or shear failure in URM walls and takes into account the effect of kinematic and static boundary conditions on the drift capacity. Finally, the performance of the analytical model is benchmarked against the test data and other empirical formulations. It shows that it yields significantly better estimates than empirical models in current codes. The paper concludes with an investigation of the sensitivity of the ultimate drift capacity to the wall geometry, static, and kinematic boundary conditions.     

土坯墙体抗震加固的试验研究

通过对4片西北地区传统土坯墙体在低周往复荷载作用下的抗震性能试验研究,对比分析了竹胶板及木柱木梁加固墙片的破坏形态、水平承载力、变形性能、骨架曲线、刚度退化曲线、滞回曲线与耗能性能。试验研究表明:加固墙片可有效提高墙体的抗震性能。在此基础上提出用竹胶板加固既有且在用的村镇土坯墙体房屋,该加固方式经济有效,又能在一定程度上保存建筑原始风貌,满足实际工程的设计要求。     

悬臂式支护结构设计中土层参数分算与合算的探讨

针对基坑支护设计中土层参数的选取问题,以悬臂桩支护结构为例,在基坑支护设计中土层参数分别采用分算与合算两种方法计算,结果表明：当各土层差异较大时,采用两种方法计算得出的最大弯矩和埋深相差较大;采用合算的结果较小,分算的结果较大.采用m法对分算与合算的设计计算结果进行悬臂桩的位移和转角的计算,其结果都能满足工程技术相关规范要求.但合算的计算结果更经济,更符合工程实际需要.     

双层打包带加固窗间墙抗震性能试验研究

地震时砌体结构窗间墙易发生破坏,为了提高其抗震性能,对高宽比为1的2组共4片墙体,其中:2片为双层打包带加固墙体,2片为原墙,进行了拟静力试验,研究墙体的破坏形态、水平承载力、滞回曲线和耗能等抗震性能。试验发现原墙发生剪切破坏,加固后墙体发生摇摆破坏,加固改变了墙体破坏模式,加固后墙体滞回曲线饱满但有捏笼,破坏荷载、延性和耗能能力都有提高,破坏时未发生剥离,表明双层打包带加固法有效地提高了窗间墙体抗震性能,对承受较大竖向应力墙体效果更好,建议加固时要加强加固层与窗下和窗上墙体的连接。