Stress seepage

Geotechnical topics covered during the first cycle include soil formation, phase relationships, soil classification, principle of effective stress, seepage, consolidation, shear strength, drained and undrained conditions, essentials of Eurocode 7, retaining walls, shallow foundations, slope stability, and field investigations. There are three class hours of lectures and two class hours of exercises per week, within a semester consisting of 15 weeks. With this list of topics, basic soil mechanics principles escape students, who attend... 

Thus the main difficulty with atmospheric sampling is created by meteorological changes which can greatly displace and dilute the seepage emissions. In addition, it is clear that the stress fields in the Earth can also influence this gas flux significantly. 

Guo, H W Xu and Z Wu, Study on the coupling influence of concrete dam base seepage, stress, and creep on structure behaviors of dam body, this volume, 2004. 

Cai J and Wu Y. 2001. Analysis of one-dimensional seepage model by coupling hydraulic head gradient, temperature gradient and stress. Chinese J. Rock Mech. Engng., 20(suppl), pp. 1026-1028. 

Chen P and Zhang Y. 1994. Coupling analysis of seepage/stress for jointed rock. Chinese J. of Rock Mech. Engng., 13(4), pp. 299-308. 

Gao H and Xia S. 1997. Three-dimensional modelling of coupled seepage and stress fields of fractured rock masses. Chinese J. of Geotech. Engng., 19(2), pp. 102-105. 

Liu J. 1987. Seepage relation in single fracture under normal stress effect. J. of Hydrogeology Engineering Geology, Vol. 2, pp. 22-27. 

Shen H, Gao H and Xia S. 1998. Experimental study on seepage characteristics of fissured rock mass with stress. Journal of Yangtze River Scientific Research Institute, 15(3), pp.35-39. 

Wang Y, Xu Z. and Su B. 1998. Four-freedom complete method for the seepage-stress coupled analysis in fractured rock masses. J. of Hydraulic Engineering, Vol. 7, pp. 55-59. 

Yang T, Tang C, Zhu W and Feng Q. 2002. Coupling analysis of seepage arul stresses in rock failure process. Chinese J. of Geotech. Engng, 23(4), pp. 489-493. 

Zhang Y and Zhang J. 1997. Experimental study of the seepage flow-stress coupling in fractured rock masses. Rock and Soil Mechanics, 18(4), pp. 59-62. 

How large a cavity can exist at depth in an intact sandstone or in a dilated and yielded sand This question is a coupled mechanics-flow issue involving seepage forces acting at the local scale (cm), pore pressure variations acting at a larger scale (m), and stress redistribution at all scales. 

In principle all the THMC processes may be involved in the geotechnical and geo-environmental problems. However, to simplify the problem for solution, only the major processes are considered for a particular problem. For example, the dam foundation problems are practically dominated by the coupled HM processes. The objectives of the solution are the interactions between the foundation stresses and deformation (the mechanical process), and the seepage pressure and flow rate (hydraulic process). Only in some special cases the thermal and/or chemical processes may also be involved, say, for dams built in cold region or on rock foundation of high solubility. 

Example 1 A study of effect of sU ess state on seepage conductivity of single natural rock fracture (MH) was conducted by one of authors of this paper. In Figure 2 the effect of normal stress on the permeability of rock joint in granite is shown. The original fracture transmissivity is reduced due to... 

To simplify the solution some authors proposed a partial coupling approach. In this case a part of inversion of interaction is not included, and the solution can be practically accepted for some special problems. Huang Tao (2002) used this approach for study of seepage field under influence of stresses and thermal action. 

A number of works are devoted to coupling analysis in the tunnel engineering. Huang Tao et al. (1999) reported a study of seepage, temperature and stress field of slope, in which the Qinglin tunnel was excavated. The main equations used are as follows. 

A cross iterative method is used in the FEM calculation. First, the initial seepage field is obtained, followed by calculation of coupled seepage and stress fields. The coupled temperature. 

Other works devoted to study of unsaturated soils can be referred to Li Xikui et al. (1998) on the coupled seepage, suction and stress fields and Yang Daiquan et al. (2(XX)) on the transfer of pore moisture, air and heat. 

Huang Tao, 2002, Coupling study among seepage-stress-temperature in fractured rock mass, Chinese J. Rock Mech. Eng., Vol.21,No.l, pp.83-87... 

Li Yaochen, Chen Jie and Zhou shunhua, 2001, Numerical simulation for a foundation reinforcement procedure using dynamic consolidation technique. Rock and Soil Mechanics,Vol.22, No.l, pp.6-ll Liu Caihua, Chen Cunxin and Fu Shaolan, 2002, Experimental study of law of seepage through single fracture in rock under normal stress, Chinese J. Rock Mech. Eng., Vol.21,No.lO, pp.1457-1461... 

Su Baoyu, Zhan Meili and Wang Yuan, 1997, Experimental study on the coupling characteristics of fracture seepage and stresses, Chinese J. Geotech. Eng., Vol. 19, No.4, pp.73-77... 

Coupling relations between seepage field and deformation field include relations among porosity and permeability change versus stress and pore pressure, as expressed in a exponential function in equation (11) and the effects of flow on mechanical... 

STUDY ON COUPLING INFLUENCES OF CONCRETE DAM FOUNDATION SEEPAGE, STRESS, AND CREEP ON STRUCTURE BEHAVIORS OF DAM BODY... 

Abstract Accidents of some arch dams show that dam failures are mainly caused by crack or failure of their foundation rocks, which are directly related to water seepage in the rock. This kind of fluid-rock interaction has an important influence on deformation and stress characters of the dam-rock system. In this paper, the stress and flow fields of dams and their foundation rocks are studied as a coupled system, using visco-elastic constitutive models and finite element solution method. The developed models and FEM technique were applied for analysing the continuous displacement of the 13 dam section of the Longyangxia Dam, and the calculated results agree well with the measured ones. 

If the dam and its base rock are affected only by gravity and seepage force, which are considered as body forces, and denoting that the tensile stress is positive, the balance differential equations expressed by displacements and general water heads can be given as... 

The basic equations for the coupling analysis of stress and seepage fields are composed of equations (I) and (2), whose boundary conditions include (a) displacement boundary condition < ) = < , (b) stress boundary condition = cr, (where... 

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