管幕内顶进箱涵时顶部管幕力学作用的试验研究

上海市中环线虹许路北虹路下立交工程是目前世界上在饱和含水软土地层中施工的横截面最大的管幕法工程。为了充分研究箱涵顶进过程中管幕的力学作用,根据相似理论,按照实际工程状况进行了室内模型试验,得到了箱涵推进过程中地面和顶部管幕的竖向位移,以及管幕下土压力的变化特征,发现箱涵前端一定范围内的地层主要表现为竖向沉降变形,顶部管幕在箱涵推进过程中起到一定的承载作用,这对于稳定箱涵前端开挖面是有利的。试验结果对实际工程的设计与施工提供了一定的参考。

Study on the behavior of the upper pipe-curtain during the advance of a box culvert within pipe-curtains by a model test

Up to now,the underpass of Shanghai Middle Ring at Beihong road through Hongxu road is a pipe-curtain project with the biggest crosssection box culvert in the world and which is constructed in saturated soft strata.In order to study the behavior of the upper pipe-curtain during the advance of the box culvert,a model test was carried out according to the theory of analogy and the conditions of the practical project.Vertical displacements of ground and the upper pipe-curtain and the variation of the earth pressures under the upper pipe-curtain were revealed from the test.It indicated that the local soil stratum in front of the box culvert mainly settled vertically and the upper pipe-curtain offered certain supporting ability during the advance of the box culvert which was advantageous for the stability of the cutting surface in the front of the culvert.The results from the model test can be taken for reference by the design and construction of practical projects.