长江下游大型桥梁建设的工程地质问题

Engineering geology problem of large bridges in the lower reach of the Yangtze River

近年来,随着经济建设的快速发展,大型和特大型桥梁等交通工程建设不断兴起。仅长江下游江苏省境内来说,400km长的河段上,在未来的10a内将要建成6座特大型桥梁。这类特大型桥梁工程建设经验少,桩型多为大直径超长灌注桩,现有规范难以满足设计需要。因此,工程地质勘测和桩基设计面临许多新的问题。通过江苏省境内几座特大长江大桥的工程地质综合研究,认为应采用区域稳定性与地基稳定性、地质分析和力学分析相结合的原则。工作重点主要有3个方面。第一,在查清工程区大地构造单元、断裂活动特征等区域地质背景的基础上,进行区域稳定性评价;第二,分析场区地层结构和构造发育情况,划分工程地质岩(层)组,并进行岩土体质量评价;第三,进行室内和现场试验,测定岩土体参数并进行优化分析,确定地基设计参数,选择桩基持力层。将这一研究思路用于苏通大桥工程,较好解决了工程建设中的难题,为大桥设计提供了可靠的工程地质依据。

In recent years, with the rapid development of national economic construction, large and super\|large bridges are gradually being set up. In the lower reach of Yangtze River in Jiangsu Province, six giant bridges will be built in future 10 years. The engineering geological investigation and pile foundation design are faced with many problems, because of being short of experience and the existent norms being incapable of meeting the needs in the piles of large diameter and super\|long. From the integrating study of several super\|large bridges in Jiangsu Province, we got some understanding knowledge, in the engineering geology study of large bridge, we should combine regional stability with foundation stability, geology analysis with mechanics analysis. The emphasis of work includes,①evaluating regional stability according to regional geology background and the activity of faults; ②dividing engineering geology strata and appraising rock\|soil mass quality based on analysis of location stratum and structure development; ③getting the parameter of rock\|soil mass and the foundation design and bearing capacity for pile from indoor and spot test. We have succeeded on the research of Sutong bridge design with aforementioned study method. 