均质土体中土钉受力的极限分析上限法  

Upper bound method for calculation of soil nail forces in homogeneous soil

作　　者：郭院成[1] 秦会来[2] 

机构地区：[1]郑州大学土木工程学院,郑州450002 [2]同济大学地下建筑与工程系,上海200092

出　　处：《岩土力学》2008年第12期3241-3245,3250,共6页Rock and Soil Mechanics

基　　金：河南省自然科学基金资助项目(No.0611010300)

摘　　要：土钉支护是加固机制上的锚固机制,土钉支护的受力和变形是随施工过程逐步变化的。采用追踪施工过程的增量计算方法,并将稳定性分析与土钉轴力计算相统一,根据稳定性要求来计算土钉受力,是土钉支护中土钉受力计算的合理途径。考虑到土钉支护中土与土钉共同作用以及潜在滑移面处土钉受力的特点,在土钉支护的稳定性分析中可以采用极限分析上限方法。根据上限方法中的相容速度场以及土钉受力与位移的关系,可确定在上限分析中每一开挖工况下土钉轴力增量的比例关系。应用上限方法的能量方程进行每一开挖工况下土钉支护稳定性的计算,即可优化求解出每一开挖工况下的土钉所需提供的能量耗散,而后依据上述确定的增量比例系数,即可求得该开挖工况下的土钉轴力增量,而各开挖工况下土钉轴力增量的积累即为最终土钉轴力。通过工程实例计算表明,上述方法是准确和有效的。In soil nailing, soil nails have the functions of reinforcement and anchorage, and the forces and deformations are changed with the construction process. On the base of the stability analysis, it is reasonable to calculate the soil nail forces by the incremental method. In soil nailing, according to the interaction between the soil and nails and the characteristic of soil nail forces at the slip surface, the upper-bound method can be used in the calculation of soil nail forces. In the calculation by the upper-bound method, the incremental coefficients of soil nail forces are decided based on the kinematical velocity field and the relationship between the forces and displacements of the soil nails. In every excavation of the cut, the energy equation of upper-bound method is used to obtain the dissipation power by the soil nails. According to the power dissipated by the soil nails and the incremental coefficients, the incremental forces of soil nails are calculated. Then, the total soil nail forces are obtained by the accumulation of the whole excavations. At last, an engineering case is presented, and the calculation results by upper-bound method are compared with other methods. The comparisons show that the upper-bound method here is effective and exact.

关 键 词：土钉支护 极限分析 上限法 增量法 

分 类 号：TU472[建筑科学—结构工程]