采用K–刚度法设计的模块式加筋土挡墙数值模拟

Numerical modeling of a reinforced soil segmental retaining wall designed using the K-stiffness method

基于一采用K–刚度法设计的模块式加筋土挡墙建立有限差分数值模型,并采用界面双曲线模型真实模拟底层模块–水平基座界面及水平基座–地基界面,研究实际模块式加筋土挡墙在工作应力下的性状,并进一步分析墙趾界面剪切特性。结果表明:数值计算的挡墙筋材应变分布、填土中各层筋材最大拉力、墙面筋材连接力和墙面最大位移值与实测值比较吻合;K–刚度法计算的填土中筋材最大拉力值与数值模拟和实测值吻合较好,但墙面连接处筋材因受地基沉降和填土压实产生的下拉力影响而大于填土中筋材最大拉力,故K–刚度法不能用于墙面筋材连接力的验算;相较于刚性地基,压缩性地基上模块式加筋土挡墙的墙趾正应力系数较大,而墙趾承担荷载比例较小;尽管基座–地基界面剪切刚度较模块–基座界面小很多,由于其承受的剪应力也很小,墙趾并不会沿着基座–地基界面发生滑移破坏,模块–基座界面对挡墙墙趾起到主要的约束作用。

A finite difference numerical model is established for a reinforced segmental retaining wall （SRW） designed using the K-stiffness method. The hyperbolic interface model is used to actually simulate the block-leveling pad and leveling pad-foundation interface. The behaviors of the field wall under working stress are investigated, and the shear characteristics of the toe interface are further analyzed. The results show that the computed reinforcement strain distribution, the maximum reinforcement loads in the fill, the connection loads and the maximum facing displacements are in agreement with the measurements. The maximum reinforcement loads in the fill computed using the K-stiffness method agree well with those computed by numerical model and the measured. However, the K-stiffness method cannot be used for verification of the connection loads because the connection loads are larger than the maximum reinforcement loads in the fill due to the effect of the down-drag force mobilized by foundation settlement and backfill compaction. Compared to the SRWs on the rigid foundation, the walls on the compressible foundation have larger factors of normal toe loads and less fractions of the total loads carried by the toe. The leveling pad will not slide along its interface with the foundation due to very small shear stress on it, although the shear stiffness of the leveling pad-foundation interface is much less than that of the block-leveling pad interface. Thus, the block-leveling pad interface plays a major role in the toe restraint.