The Analysis And Prediction Of Tunnelling-induced Building Deformations

Based on field data from home and abroad, mainly those from London, a systematic research is conducted in this thesis to discuss the deformation laws of ground and structure, and some practical methods are suggested to predicting the ground settlement, structure deformation.Firstly, on the ground settlement, the classic empirical method, Gaussian equation suggested by Peck (1969) is evaluated in detail based on field data, and the typical key parameters for some big cities of China are suggested. The law of subsurface deformation has been studied compared with the equation by Mair et al (1993), and a modified equation, which has a broader adaptability, is suggested.Secondly, on the ground settlement, a non-uniform convergence mode is introduced to the Stochastic Medium Model (SMM) method to achieve a better prediction of the ground deformation. The theoretical background and practical results of the SMM method and Peck method are compared and discussed, and the procedure to determine the key parameters used in SMM method is suggested based on the experience from the application of the Peck method.Thirdly, on the structure response to the ground deformation, the mathematical and physical definitions of the twist for a plane, and a calculation method are proposed through the theoretical analysis on the building deformation modes. This method is confirmed by a case study.Fourthly, on the structure response to the ground deformation, the three-dimensional deformation response of the buildings is analyzed in depth from two extensive case studies in London. The deformation mode of the structure is discussed and it is found out that the deflection of a typical multi-storey building is mainly caused by shear deformation of the structure. So, it is reasonable to use shear stiffness to describe the structure stiffness in the building deformation prediction models rather than bending stiffness.Fifthly,on the building settlement prediction,an important observation is put forward that the settlement profiles of the building also can be fitted by the Gaussian equation by using a larger trough-width parameter K influenced by the structural stiffness. An empirical relationship between the parameter K and the shear stiffness of the building has been suggested which can be used to predict the trough parameter according to the building stiffness, so that a'Stiffness Modified Method'is established, which is a simple, but efficient method that considered the result of the complicated tunnel-soil-structure interaction effects.