非均质填土刚性挡墙的地震土压力分析

Analysis of seismic earth pressure for rigid retaining wall with inhomogeneous backfilled soil

针对目前采用剪切梁模型计算挡墙地震土压力时,均假定墙后土层为均质土层,提出了采用离散化剪切梁的分析模型,计算墙后土层为非均质时刚性挡墙的地震土压力.首先,假定剪切模量随深度成幂函数分布,推导了非均质土层中连接弹簧的剪切刚度;再对不同剪切模量情况下地震引起的土压力增量的分布形式、土压力合力增量和合力增量作用点等进行分析讨论;最后,对该模型与Veletsos模型和Scott模型的计算结果进行对比分析.结果表明:土层的剪切模量分布形式对土压力增量的分布形式、土压力合力增量和墙底剪力增量影响显著,对合力增量作用点和墙底剪力增量的放大倍数影响很小.

Seismic earth pressure of retaining wall is often calculated based on shear-beam models on the assumption of homogeneous backfilled soil at present. The discrete shear-beam mode was proposed to cal- culate the pressure of rigid retaining wall with inhomogeneous backfilled soil. The shear stiffness of the spring in non-homogeneous backfilled soil was deduced by assuming the shear modulus distribution of power function with depth. According to the different varied shear modulus and seismic earth pressure distribution, the resultant earth pressure and acting point were analyzed. The calculated results based on the proposed model were compared with those from Veletsos model and Scott model. The results show that the distribution form of shear modulus has significant influence on seismic earth pressure increment distri- bution, the resultant earth pressure increment and the base shear increment, but has little influence on the application points of resultant earth pressures increment and the amplification factor of base shear increment.