沉管隧道地震响应分析的并行计算

采用全三维非线性建模方法建立了沉管隧道总体有限元模型,模型规模上节点总数超过100万,单元总数超过120万。由于系统的非线性,以及地震激励是一种时间历程,沉管隧道地震响应数值模拟的实质是一个超大规模非线性系统的瞬态响应计算问题,因此导致目前在地震安全性评价领域普遍采用的串行算法、串行软件和普通的计算机无法胜任此工作。根据所用超级计算机的体系结构特点,采用并行区域分解算法,通过对沉管隧道总体模型合理分区来进行地震响应分析。地震波载荷选用调幅后的唐山地震波,应用通用的非线性动力分析有限元程序LS-DYNA进行求解,计算结果可为隧道的抗震设计提供有力依据。

PARALLEL PROCESSING OF SEISMIC RESPONSE ANALYSIS FOR IMMERSED TUNNEL

Using the high performance computer SGI Onyx3800,this paper introduced finite element method in simulating the seismic response of the immersed tunnel in Shanghai. Consisting the immersed tunnel,soil and river,a large three-dimensional finite element model was finished in the CAE software;and the number of nodes and elements in final finite element model exceeds 1.2 million and 1 million respectively. The seismic response numerical simulation for immersed tunnel is a transient response analysis of large-scale system. Thus,it is impossible to finish this simulation by serial algorithm,serial software and PC. The ultimate calculation adopted explicit dynamic algorithm and parallel domain decomposition method. The recursive coordinate bisection method was used and improved considering the construction feature of immersed tunnel. The result reveals the weak joints in this immersed tunnel under Tangshan seismic waves. It can also provide data and references to the aseismatic design of immersed tunnel and its flexible joints.