Study On Three-Tube Parallel Shield Tunnel Of Subway Approaching Constructed In Mollisol By Centrifugal Model Test

In recent years, with the development of underground engineering such as subway, many approaching construction of underground engineering has appeared. Limit by the existing construction or geological conditions and the requirement of the comprehensive exploitation of underground engineering, the distance of between tunnels or tunnel and other construction becomes shorter and shorter. The new tunnels constructed in short distance at the same phase appear more and more. That must make the relation between tunnels complicated and do all kinds of bad influence to tunnel construction.In course of the approaching construction of underground engineering, the construction of later building structure will change the mechanics case of early building structure and brings all kinds of bad influence to the early building one, such as load bearing capacity of structure decreasing, structure breaking, or too much deformation of structure and structure intrude into clearance. At the same time, the mechanics mode of later building structure is not the same as that of single cave excavated. Its initial stress field is disturbed time and time again, and once more by excavating of later. So the mechanics mode of the later is not symmetrical generally and shows right smart variability. This brings the safety problem of early building structure and the complexity problem of later building structure. So it is necessary to study on the complexity stress mechanics and optimize the construction subsequence.This thesis is base on the project of "Control technique research on three-tube parallel shield tunnel of subway approaching constructed in Mollisol", a project from Construction Ministry. Two groups of centrifugal model tests have been done with one group with stratum reinforced and another not. The prototype is three-tube parallel shield tunnel of R413 bid segment of the 9th route of Shanghai track traffic. The country rock pressure, endogen force of lining and displacement of ground surface have been determined during different construction progress. The regularities of distribution of country rock pressure, endogen force of lining and displacement of ground surface when the three-tube parallel shield tunnelapproaching constructed under different case are gained by test data analysis. The theory of centrifugal modeling is expounded particularly as well as the design and model-making, the measure system and the result of the experiments. Conservatory measures of three-tube parallel shield tunnel of subway approaching constructed in Mollisol have been brought forward, which have some reference value to the same kind of engineering.