交通荷载作用下黄河三角洲低液限粉土地基累积沉降规律研究  

Traffic-induced settlement of subgrade of low liquid limit silt in Yellow River delta

作　　者：崔新壮[1] 

机构地区：[1]山东大学,山东济南250061

出　　处：《土木工程学报》2012年第1期154-162,共9页China Civil Engineering Journal

基　　金：国家自然科学基金(51078222;50708056);山东大学自主创新基金杰出青年培养项目(2010JQ001);山东省自然科学基金(ZR2011EEM012)

摘　　要：低液限粉土在黄河三角洲分布非常广泛,属液化土,在交通荷载反复作用下地基会产生很大的累积沉降,但目前对粉土地基累积沉降规律研究很少。为此,研发一套适于研究地基累积沉降的落锤式交通荷载模拟装置,通过改变锤的落距等参数能够实现对不同车载的模拟。用该装置对黄河三角洲低液限粉土地基累积沉降进行现场模拟,同时基于Chai-Miura土体累积变形模型对累积沉降进行数值计算与分析,并与试验结果进行比较。现场试验结果表明:累积沉降和超静孔隙水压力基本上均随作用次数增大先快速增大,然后逐渐趋于稳定,而且均随交通荷载的增大而增大;随着加载次数增大,地基会出现翻浆冒泥现象;加载完毕后沉降和孔压均在初期变化较快,随后逐渐变缓。累积沉降的计算结果与试验结果总的来说符合较好,但在交通荷载作用初期,计算结果偏大,这是因为Chai-Miura模型是由不排水试验得到的,而实际地基在车载作用过程中始终处于部分排水状态。The low liquid limit silt in Yellow River delta is liquefiable, and under traffic load, the cumulative settlement of the natural subgrade can be significant. In order to study the cumulative settlement of subgrade in situ, a fallingweight simulation equipment of traffic load was developed. By adjusting the technical parameters such as the falling distance of the weight, different types of traffic loads can be simulated. With the equipment, in situ tests were carried out on silt subgrade. Based on the Chai-Miur cumulative deformation model of soil, the traffic-load-induced cumulative settlement of silt subgrade was calculated and compared with the test results. Tests indicated that the settlement and excess pore water pressure rapidly grew initially and then tended to be stable with the increase of the loading time, and increased with the increase of the traffic load. With the liquidation of natural subgrade induced by traffic loads, mudpumping was observed. After load was terminated, the settlement and pore pressure varied rapidly initially with time and then slowly. The tendency of the calculated cumulative settlement with loading time generally agreed well with the test, whereas in the initial loading period the calculated settlement was obviously larger than the test value, mainly because Chai-Miur model is for undrained tests, however, while the subgrade under traffic load was partially drained.

关 键 词：道路工程 交通荷载 低液限粉土 累积沉降 

分 类 号：U416.1[交通运输工程—道路与铁道工程]