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Hangzhou, China

Liang R.-Z.,Zhejiang University | Xia T.-D.,Zhejiang University | Lin C.-G.,Ningbo University | Yu F.,Zhejiang Sci-Tech University | Wu S.-M.,Insigma Group Co.
Journal of Central South University | Year: 2015

Tunnelling-induced long-term consolidation settlement attracts a great interest of engineering practice. The distribution and magnitude of tunnelling-induced initial excess pore water pressure have significant effects on the long-term consolidation settlement. A simple and reliable method for predicting the tunnel-induced initial excess pore water pressure calculation in soft clay is proposed. This method is based on the theory of elasticity and SKEMPTON’s excess pore water pressure theory. Compared with the previously published field measurements and the finite-element modelling results, it is found that the suggested initial excess pore water pressure theory is in a good agreement with the measurements and the FE results. A series of parametric analyses are also carried out to investigate the influences of different factors on the distribution and magnitude of the initial excess pore water pressure in soft ground. © 2015, Central South University Press and Springer-Verlag Berlin Heidelberg. Source

Mu L.-L.,Tongji University | Huang M.-S.,Tongji University | Wu S.-M.,Insigma Group Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

Evaluation of soil responses induced by excavations, which are now mainly computed by finite element method, is required to estimate the damages of potential buildings caused by excavations. Using proper soil parameters is a key ingredient when computing soil responses, assuming the model represents the actual soil responses in a reasonable way. The soil parameters are usually identified from laboratory experiments performed on tube samples or from in-situ tests, but large uncertainties are associated with these methods for most projects. The inverse analysis is a quantitative technique which allows one to select parameters to fit the responses of soil from field observations. The technique is applied to the results of field performance data collected from an excavation made through Chicago clays. The results of the computed soil responses based on the hardening soil model (HS) and hardening model-small (HSS) model found in the computer code PLAXIS are compared to illustrate the problems likely encountered in practical application of finite element simulations. Based on the well chosen parameters, the soil movements induced by the excavation are computed reasonably. Source

Li D.-C.,Tongji University | Qian J.-G.,Tongji University | Wu S.-M.,Insigma Group Co. | Liu G.-S.,Insigma Group Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

The finite element method is used to analyze the effects of excavation on the behaviors of underpinning piles in excavation area. First, numerical model is adopted to simulates the interaction of structure-foundation-soil and estimate negative effects of the rebound deformation of underpinning piles on the top plate. Based on the deformation and bearing state of the underpinning piles, the adjusting deformation from oil jack is available. It is demonstrated that a constant level of load should be applied to the top of the underpinning piles so that the top plate has the "zero" additional deformation. During the process of loading adjustment, the axial force at the upper part of the underpinning pile increases and the axial force at the lower part decreases as the depth of excavation increases gradually. When the depth of excavation is over 5 meters, negative skin friction occurs at the lower part of pile and results at the axial tension in the bottom. Source

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