散货码头堆场地基推移破坏离心模型试验研究

Centrifuge modeling and translation failure mechanism analysis of a bulk cargo terminal yard ground

某散货码头堆场地基中有一软弱的淤泥质黏土层,堆场荷载区地基先采用真空联合堆载预压处理,再对两侧地基进行水泥搅拌桩加固处理,但在矿石试堆载过程中,淤泥质黏土层最厚处的堆场发生了严重的推移破坏。为研究推移破坏原因,通过开展大型离心模型试验,模拟矿石堆载体的填筑过程,测得矿石堆载体和堆场地基表面竖向和水平向位移;判断位移变形发展过程中的转折点,得到堆场地基的极限承载力;通过矿石堆载荷载作用下堆场地基剖面上发生的位移矢量场,分析再现堆场地基推移破坏现象和形成机制。分析结果表明:该堆场地基承载力由深厚软弱土层控制,承载力不足导致矿石堆载填筑过程中堆场地基出现严重下陷,下沉的浅表两层土体挤占下卧淤泥质黏土层空间,迫使其向阻力较小的南柳河一侧挤推,造成大范围的推移破坏。根据分析结果,提出了对堆场软土层进行改良或采用复合地基的修复加固途径。

A bulk cargo wharf yard foundation contained a weak layer of muddy clay,although two side foundations of the yard were reinforced by cement mixing piles.However,a sliding failure as well as lateral translation collapse occurred where the thickest muddy clay was during the fill of ore heap on trial.In order to find the real reason for the sliding failure and lateral translation collapse and to provide the design basis and reference for repair,a large centrifugal model,test was conducted.The filling process of the ore heap was simulated,and the vertical and horizontal displacement deformation of the surface of the ore heap and the yard foundation was measured.Firstly,the turning points of the displacement and deformation development were identified,and the critical point of stability and the ultimate bearing capacity of yard foundation were obtained.Secondly,based on the displacement field on the cross section of yard ground under the load of the ore heap,the failure mode and the development process of the sliding and translation failure of the bulk cargo wharf foundation were analyzed and discussed.The results showed that in the filling of the ore heap,its shallow subsoil subsidence and sliding failure first appeared due to its insufficient bearing capacity.Secondly,the subsidence of shallow subsoil occupied the space of underlying soft muddy clay layer,forcing it to lateral translation towards the side of the Nanliu River,resulting in a wider range of collapse.