Reassessment of the effect of water saturation on intact rock and fractured Rrck

• Autorzy: Reddish D. J. , Li Z. , Sheng Y.

Warianty tytułu

PL

Powtórna ocena wpływu nasycenia wodą na zachowanie skały nienaruszonej i skał popękanych

• Języki publikacji: EN

Abstrakty

EN

Water is one of the many factors influencing the strength of geomaterials. In this paper, multistage triaxial compressions were performed to investigate the weakening effect of water on intact and fractured sandstone specimens. Laboratory testing results are presented and discussed with particular reference to the change of the mechanical properties of the rock. A trend of strength reduction for both intact and fractured rocks can be generalized from the testing results. It is also observed that the fractured rock is more reactive to the water even though no apparent soluble gouge is sandwiched in the related rock fractures. Additionally, theoretical formulations are derived to characterize the strength reduction on the basis of the understanding of the physical process. Properties of a single rock joint are correlated with the tangential plastic energy of the shearing plane with the non-associated plastic flow rule during shearing. The degree of saturation Sw is introduced into Patton's model as an additional parameter to predict the shear strength evolvement with the degree of water saturation.

PL

Woda jest jednym z wielu czynników decydujących o wytrzymałości geo-materiałow. W niniejszej pracy przeprowadzono próby wielostopniowego trójosiowego ściskania skał, w celu zbadania w jaki sposób woda będzie zmniejszać wytrzymałość nienaruszonych i popękanych próbek piaskowca. Przedstawiono i przedyskutowano wyniki badań laboratoryjnych, zwłaszcza w kontekście zmian właściwości mechanicznych skał. Na podstawie wyników badań zauważono wyraźny trend do obniżenia wytrzymałości zarówno próbek skał nienaruszonych jak i popękanych. Zauważono także, że skały popękane bardziej reagują na wodę, pomimo, że w pęknięciach nie stwierdzono żadnych substancji rozpuszczalnych. Ponadto, opracowano teoretyczne wzory określające obniżenie wytrzymałości, w oparciu o zachodzące procesy fizyczne. Właściwości pojedynczego ciosu skały skorelowano z energią pochodzącą od odkształcenia stycznego płaszczyzny ścinania bez powiązania z zasadą płynięcia plastycznego w czasie ścinania. Do modelu Pattona wprowadzono stopień nasycenia Sw, jako dodatkowy parametr pozwalający na przewidywanie zmian odporności na ścinanie przy zmianie stopnia nasycenia wodą.

Słowa kluczowe

EN

effect of water; strength; post failure strength; fractured rock

PL

wpływ wody; wytrzymałość; wytrzymałość po spękaniu; popękane skały

• Wydawca: Instytut Mechaniki Górotworu PAN
• Czasopismo: Archives of Mining Sciences
• Rocznik: 2006
• Tom: Vol. 51, no 1
• Strony: 13--34
• Opis fizyczny: Bibliogr. 32 poz., rys., tab., wykr.

Twórcy

autor

Reddish D. J.

autor

Li Z.

autor

Sheng Y.

• Nottingham Centre For Geomechanics, School Of Civil Engineering, University Of Nottingham, Nottingham, Ng7 2rd, Unlted Kingdom

Bibliografia

• Alonso, E.E., Gen, S.A.., Josa, A., 1990. A constitutive model for partially saturated soils. Geotechnique, 40, 405-430.
• Aydan, T.A., Kawamoto, T., 1993. Squeezing potential of rocks around tunnels; theory and prediction. Rock Mechanics and Rock Engineering, 26(2),137-163.
• Ballivy, G., Ladanyi , B.,Gill , D.E., 1976. Effect of water saturation history on the strength of low-porosity rocks. Soil specimen preparation for laboratory testing, ASTM STP, 599, 4-20.
• Barla, M., Barla, G., 2000. Continuum and discontinuum modelling in tunnel engineering. Pubblicato su Rudarskogeolosko-naftni zbornik, 12,45-57.
• Barla, M., Barla, G., Repetto, L., 1999. Continuum and discontinuum modelling fordesign analysis of tunnels. Proc. 9th ISRM International Congress, A.A. Balkema Rotterdam, 163-168.
• Barton, N., 1973 Review of a new shear strength criterion for rock joints. Engineering geology, 7, 287-332.
• Baud, P., Zhu, W., Wong, T. 2000. Failure mode and weakening effect of water on sandstone. 1. Geophys. Res., 105(B7), 16371-16389.
• Bobet, A., 2003. Effect of pore water pressure on tunnel support during static and seismic loading. Tunnelling and Underground Space Technology, 18(4),377-393.
• Botts, M.E., 1986. The effects of slaking on the engineering behaviour of clay shales. PhD thesis, University of Colorado.
• Broch, E., 1979. Changes in rock strength by water. Proc. IV. Int. Soc. Rock Mech., Montreux, 1,71-75.
• Chenevert, M.E., 1970. Shale alteration by water adsorption. 1. Petroleum Technology, 1141-1148.
• Colback, P.S., Wiid, B.S., 1965. The influence of moisture content on the compressive strength of rocks. Proc. Third Canadian Symposium on Rock Mech., Toronto pp.65-83.
• Dube ,A.K, Singh, B., 1972. Effect of humidity on tensile strength of sandstone. J. Mines, metals and fuels, 20(1), 8-10.
• Duperret, A., Taibi, S., Mortimore, R.N., Daigneault, M., 2005. Effect of groundwater and sea water weathering cycles on the strength of chalk rock from unstable coastal cliffs of NW France. Engineering Geology, 78, 321-343.
• Gili, J.A., Alonso , E.E., 2002. Microstructural deformation mechanisms of unsaturated granular soils. Int. J. for Numerical and Analytical Meth. In Geomech., 26, 433-468.
• Grasselli, G., Egger, P., 2003. Constitutive law for the shear strength of rock joints based on three-dimensional surface parameters. Int. J. Rock Mech. Min. Sci. 40(1), 25-40.
• Hawkins, A.B., Mc Connel , BJ., 1992. Sensitivity of sandstone strength and deformability to changes in moisture content. J. Eng. Geology, 25, 115-130.
• Jardine, R.J., Gens, A. Hight, D.W., Coop, M.R., 2004. Developments in understanding soil behaviour. Proc., Advance in Geotechnical engineering, ICE, London, UK, 103-206.
• Jing, L., Nordlund, E., Stephansson, O., 1994. A 3-D constitutive model for rock joints with anisotropic friction and stress dependency in shear stiffness. Int. J. Rock Mech. Min. Sci., 31(2),173-178.
• Lade, P.V., De Boer, R., 1997. The concept of effective stress for soil, concrete and rock. Geotechnique, 47(1), 61-78
• Li, Z., Reddish, DJ., 2004. The effect of groundwater recharge on broken rocks. Int. J. Rock Mech. Min. Sci., 41 (SI), 280-285.Masuda, K., 2001. Effects of water on rock strength in a brittle regime. J. Structural Geology 23(11), 1653-1657.
• Morrow, C.A., Moore, D.E., Lockner, D.A., 2000. The effect of mineral bond strength and adsorbed water on fault gouge frictional strength. Geophysical Research Letters, 27(6), 815-818.
• Parate, N.S., 1973. Influence of water on the strength of limestone. Transaction of Society of mining engineers, AIME.254,127-131.
• Patton, F.D., 1966. Multiple modes of shear failure in rock. Proc. 1st Cong. Int. Society of Rock Mech., Lisbon, Portugal, 509-513.
• Plesha, M.E., 1987. Constitutive models for rock discontinuities with dilatancy and surface degradation. Int. J. Numer. Anal. Methods Geomech. 11,245-362.
• Rao, K.S., Venkatappa Rao, G. & Ramamurthy, T., 1987. Strength of sandstone in saturated and partly saturated conditions. Geotechnical Engineering, 18,99-126.
• Swift ,G., Reddish, DJ., 2002. Stability problems associated with an abandoned ironstone mine. Bulletin of Engineering Geology and the Environment, 61(3), 227-239.
• Terzaghi, K., 1923. Die Berechnung der Durchlassigkeitsziffer des Tones aus dem Verlauf der hydrodynamischen Spannungser-scheinungen. Sitz Akad. Wien Math-naturw KI. Abt. Da, 132, 105-124.
• Wang, J.G., Ichikawa, Y., Leung, C.F., 2003. A constitutive model for rock interfaces and joints. Int. 1. Rock Mech. Min. Sci., 40(1), 41-53.
• Wen, B.P., Aydin, A. 2005. Mechanism of a rainfall-induced slide-debris flow: constraints from microstructure of its slip zone. Engineering Geology, 78 (1-2), 69-88.
• Van Eeckhout, E.M., 1976. The mechanism of strength reduction due to moisture in coal mine shales. Int. J. Rock Mech. Min. Sci. and Geomech. Abstr., 13,61-67.
• Yang, I., 2004. Pore pressure coefficient for soil and rock and its relation to compressional wave velocity. Geotechnique, 55(3), 251-256.