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Song J.-H.,Nanjing Southeast University | Song J.-H.,Henan University of Urban Construction | Miao L.-C.,Nanjing Southeast University | Dai S.-M.,Shanghai Tunnel Engineering Construction Co. | Ma Y.,Shanghai Tunnel Engineering Construction Co.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2013

It is a difficult problem to analyze the pore water pressure monitored in the field while tunnelling. Based on the tunnel constructed in Shanghai of China, a finite element model for shield tunnelling is established, which can study the effects of construction parameters. The model is validated by comparing the calculated results with the data monitored in the field. The effects of the construction parameters including the face thrust force, grouting pressure, excavation rate, water head at the face, cover depth and soil permeability on the maximum excess pore water pressure are analyzed. Then a fitting formula for the pore water pressure is obtained based on the calculated result. By comparison between the analytic solution and the data monitored in the field, it is obtained that the 3D coupled mechanical and hydraulic method is a good way to analyze the pore water pressure disturbed by shield tunnelling. The larger the maximum pore water pressure, the larger the ground settlement. So the pore water pressure monitored in the field can be used to analyze the fitness of the construction parameters. For Yingbinsanlu tunnelling project in Shanghai, the monitored pore water pressure is compared with the numerical results, and it is concluded that the construction parameters can be changed in time to decrease the ground settlement.


Song J.,Henan University of Urban Construction | Miao L.,Nanjing Southeast University | Hu B.,Shanghai Tunnel Engineering Construction Co. | Liang J.,Hohai University
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2014

Model tests were carried out to analyze the differences of the soil arching above the tunneling face between the dry sand and the saturated sand. The test system, including the glass box, the tunneling model and the measure system, is designed. Then the forming process of the arching above the tunneling face is obtained with different sand particle size, different cover depth, and different water condition. The test results show that the forming process of the soil arching is delayed by the ground water and the arching height can be decreased between 10% and 15%. The water also decreases the ground settlement by lowering the height of the soil arching above the tunneling face. In the end, it can be concluded that the lateral earth pressure coefficients of the prism above the wedge should be updated because the height of the soil arching is lowered by the ground water.


Song J.,Henan University of Urban Construction | Chen K.,China University of Mining and Technology | Ma Y.,Shanghai Tunnel Engineering Construction Co. | An L.,Henan University of Urban Construction
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2016

In shield tunnlling there are many factors can affect the stability of the thrust force such as the changes of geology conditions, soil cutting by the cutter head, and the regular stop of the shield for segment assembly. The excess pore water pressure caused by the fluctuations force can be accumulated so large that the stability of the tunnel face could be affected. The layered soil analysis model was established at first and the calculation method of the excess pore water pressure near tunnel face was obtained by combining the Terzaghi's one-dimensional consolidation theory. Then the calculation method of the effect of the excess pore water pressure on the tunnel face stability was given out using the wedge analysis model. From the calculation result it can be concluded that the safety factor of tunnel face can be reduced by the excess pore water pressure. So the effect of the fluctuations thrust force should be considered in the calculation of the minimum support face pressure. At last the excess pore water pressure and the decreasing coefficient of safety factor with different construction conditions were given out through parameter analysis. © 2016, Science Press. All right reserved.


Liao Y.-L.,Tongji University | Zhang Z.-X.,Tongji University | Zhang G.-J.,Shanghai Tunnel Engineering Construction Co.
Yantu Lixue/Rock and Soil Mechanics | Year: 2011

How to timely identify cemented soil stability for Qianjiang tunnel breakthrough is discussed in terms of monitoring indices and monitoring range. Firstly, based on the plate theory and elastoplasticity theory, the water and earth pressures on the cemented soil are presented which can timely identify the cemented soil stability during shield tunnelling breakthrough as well as two indices K0, Ksf. Then, a failure mode for the cemented soil is put forward on the basis of existing failure modes to underlie the observation point layout, and verified by model test. The cemented soil stability can be estimated timely by calculating K0, Ksf from the measurement values when measuring points are distributed rationally.


Wan M.,ParisTech National School of Bridges and Roads | Wan M.,Shanghai Tunnel Engineering Construction Co. | Delage P.,ParisTech National School of Bridges and Roads | Tang A.M.,ParisTech National School of Bridges and Roads | Talandier J.,Andra Inc
International Journal of Rock Mechanics and Mining Sciences | Year: 2013

A possible option for the disposal of high level long lived radioactive waste is to store the waste in galleries excavated at great depth in clays or claystones. In such conditions, the walls of the galleries will be successively subjected to desaturation induced by ventilation followed by resaturation once the galleries are closed. Partial saturation also affects laboratory samples, due to the added effects of coring, transportation, storage and trimming. In this study, a series of tests was conducted to investigate the water retention properties of the Callovo-Oxfordian claystone (in which the ANDRA Underground research laboratory in France has been excavated) under drying/wetting cycles so as to provide a complete description of the changes in water content, volume and degree of saturation from the as-provided state. The results show that water content changes between 3% (at 150. MPa of suction) and 12% at zero suction, with a shrinkage of 1.4% (at 150. MPa of suction) and a 7% swelling at zero suction. The data obtained complete existing data by defining the initial state with respect to the main drying and wetting paths and by providing volume changes along the suction cycles. Hysteresis effects are also evidenced. Irreversible volume changes are assumed to be due to micro-crack generation and incomplete recovery. The changes in degree of saturation with respect to water content appeared to be reversible, an important fact to consider when simulating volume changes in COx. © 2013 Elsevier Ltd.


Wan M.,Shanghai Tunnel Engineering Construction Co. | Delage P.,ParisTech National School of Bridges and Roads | Tang A.M.,ParisTech National School of Bridges and Roads | Talandier J.,Andra Inc
Unsaturated Soils: Research and Applications - Proceedings of the 6th International Conference on Unsaturated Soils, UNSAT 2014 | Year: 2014

High level long lived radioactive waste might be stored in galleries excavated at great depth in clays or claystones. During storage operations, the walls of the galleries will be successively subjected to desaturation due to ventilation followed by resaturation once the galleries are closed. Partial saturation may also affect laboratory samples, due to the added effects of coring, transportation, storage and trimming. This paper describes an investigation about the water retention properties of the Callovo-Oxfordian claystone (in which the ANDRA Underground research laboratory in France has been excavated) under drying/wetting cycles. A complete description of the changes in water content, volume and degree of saturation from the as-provided state is made. Data show that water content changes between 3+ACU- (at 150 MPa of suction) and 12+ACU- At zero suction, with a shrinkage of 1.4+ACU- (at 150 MPa of suction) and a 7+ACU- swelling at zero suction. The data obtained complete existing data by defining the initial state with respect to the main drying and wetting paths and by providing volume changes along the suction cycles. Hysteresis effects are also evidenced. Irreversible volume changes are assumed to be due to micro-crack generation and incomplete recovery. © 2014 Taylor & Francis Group.

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