基于周边既有建筑物承载能力的基坑变形控制标准

邻近既有建筑物由于基坑开挖引起的土体位移作用而产生附加变形。首先提出基坑开挖对邻近既有建筑物影响的位移控制有限元分析方法(DCFEM)，通过与离心模型试验的对比，验证其合理性。然后，对新修订的上海《基坑工程技术规范》的基坑环境保护标准进行探讨，通过算例分析，指出其不合理之处。最后，考虑建筑物自身的承载能力，采用DCFEM法进行分析，提出基于周边建筑物承载能力的基坑变形控制标准。

SOME THEORETICAL QUESTIONS OF COMPOSITE SOIL NAILING WALL AND DISCUSSION ON TECHNICAL CODE FOR COMPOSITE SOIL NAILING WALL IN RETAINING AND PROTECTION OF EXCAVATION

Four selected engineering accident examples of composite soil nailing walls are particularly analyzed and studied；and some conclusions are drawn as follows. (1) When the safety factor of global stability checking of composite soil nailing wall meets the requirements of specification，the local stability can not be checked. (2) The “design bearing capacity” of nailing is difficult to be checked；and the“pull-out resistance of acceptance” could be adopted as the quality test standard and the basis of rod body strength design. (3) 6 kinds of composite soil nailing wall failure modes of the 13 kinds should be mainly checked and the other kinds could adopt structural measures，and so on. In addition，the research results include that：application conditions of composite soil nailing wall，methods of basic test and acceptance test of soil nailing，treatment principles of excavation of pit inside pit and edge-corner effect，exploration and survey requirements for surrounding environment，solution to bad engineering plan and coordination and lack of geotechnical engineering professional experience，etc. These theories research results have been reflected in the new implemented national standard of Technical Code for Composite Soil Nailing Wall in Retaining and Protection of Excavation.