The infiltration, evaporation and variation of the groundwater table have significant effects on the
suction stress of the soils and the supporting earth pressures of the foundation excavation. The distribution
of the suction stresses above the ground water table is derived under different fluxes at the ground surface,
according to the soil-water characteristic parameters and the effective degree of saturation. In consideration of
the cohesive stress formed from the soil suction stress and the relevant anti sliding effect, the calculation model
of supporting earth pressures for foundation excavation is established by the variational limit equilibrium method
under the steady flow condition. The evolution of the supporting earth pressures is studied in detail for foundation
excavation under different fluxes at the ground surface. The effects of the soil-water characteristic parameters, the
ground water table and the internal friction angle on the supporting earth pressures are discussed. The results
show that the suction stress is reduced because of the infiltration, and thus the supporting earth pressure increases.
The larger the air-entry pressures and the pore size are, the smaller the supporting earth pressures are. The higher
the ground water table is, the larger the supporting earth pressures are. In order to reduce the construction risk,
the effects of the suction stress and the evolution of the potential critical sliding surface should be considered
during the calculation of the supporting earth pressures.
LI Jingpei, CAO Xiaobing, LI Lin
. Supporting Earth Pressures for Foundation Excavation Considering Suction Stress of Soil[J]. Journal of Shanghai Jiaotong University(Science), 2020
, 25(4)
: 486
-494
.
DOI: 10.1007/s12204-020-2187-y
[1] ALEOTTI P. A Warning system for rainfall-induced shallow failures [J]. Engineering Geology, 2004, 73(3):247-265.
[2] RAHARDJO H, ONG T H, REZAUR R B, et al. Factors controlling instability of homogeneous soil slopes under rainfall [J]. Journal of Geotechnical and Geoenvironmental Engineering, 2007, 133(12): 1532-1543.
[3] BISHOP A W, BLIGHT G E. Some aspects of effective stress in saturated and partly saturated soils [J].G′eotechnique, 1963, 13(3): 177-197.
[4] FREDLUND D G, MORGENSTERN N R. Stress state variable for unsaturated soils [J]. Journal of Geotechnical Engineering Division, 1977, 103(5): 447-466.
[5] FREDLUND D G, MORGENSTEM N R, WIDGER R A. The shear strength of unsaturated soils [J]. Canadian Geotechnical Journal, 1978, 15(3): 313-321.
[6] VANAPALLI S K, FREDLUND D G, PUFAHL D E,et al. Model for the prediction of shear strength with respect to soil suction [J]. Canadian Geotechnical Journal,1996, 33(3): 379-392.
[7] LU N, LIKOS W J. Unsaturated soil mechanics [M].New York, USA: Wiley, 2004.
[8] LU N, LIKOS W J. Suction stress characteristic curve for unsaturated soil [J]. Journal of Geotechnical and Geoenvironmental Engineering, 2006, 132(2): 131-142.
[9] LU N, GODT J W, WU D T. A closed-form equation for effective stress in unsaturated soil [J]. Water Resources Research, 2010, 46(5): W05515.
[10] ZHAN L T, NG C W W. Effect of suction on shear strength and dilatancy of an unsaturared expansive clay [J]. Chinese Journal of Geotechical Engineering,2007, 29(1): 82-87 (in Chinese).
[11] KONG L W, ZHOU B C, BAI H, et al. Experimental study of deformation and strength characteristics of Jingmen unsaturated expansive soil [J]. Rock and Soil Mechanics, 2010, 31(10): 3036-3042 (in Chinese).
[12] SUN D A, SUNWJ, XIANG L. Effect of degree of saturation on mechanical behaviour of unsaturated soils and its elastoplastic simulation [J]. Computers and Geotechnics, 2010, 37: 678-688.
[13] SUN D A, ZHANG J R, GAO Y, et al. Influence of suction history on hydraulic and stress-strain behavior of unsatrurated soils [J]. International Journal of Geomechanics, 2016, 16(6): 1-9.
[14] ZHANG J R, SUN D A, ZHOU A N, et al. Hydromechanical behaviour of expansive soils with different suctions and suction histories [J]. Canadian Geotechnical Journal, 2016, 53(1): 1-13.
[15] ZHANG L, ZHANG L L, CHENG Y, et al. Slope stability under rainfall infiltration considering internal erosion [J]. Chinese Journal of Geotechnical Engineering,2014, 36(9): 1680-1687 (in Chinese).
[16] HUANG M S, JIA C Q. Stability analysis of soil slopes subjected to unsaturated transient seepage [J]. Chinese Journal of Geotechnical Engineering, 2006, 28(2): 202-207 (in Chinese).
[17] LI N, XU J C. Development and application of three-dimensional rainfall infiltration module based on ABAQUS [J]. Chinese Journal of Geotechnical Engineering,2015, 37(4): 667-674 (in Chinese).
[18] TANG D, LI D Q, ZHOU C B, et al. Slope stability analysis considering antecedent rainfall process [J].Rock and Soil Mechanics, 2013, 34(11): 3239-3248 (in Chinese).
[19] LI Z P, ZHANG M. Study on effects of rainfall infiltrationb on safty of excavition slope [J]. China Safety Science Journal, 2000, 10(3): 16-22 (in Chinese).
[20] GARDNER W R. Some steady-state solutions of the unsaturated moisture flow equation with application to evaporation from a water table [J]. Soil Science, 1958,85(4), 228-232.
[21] BAKER R, GARBER M. Theoretical analysis of the stability of slopes [J]. G′eotechnique, 1978, 28(4): 395-411.
[22] LESHCHINSKY D, ZHU F. Resultant force of lateral earth pressure in unstable slopes [J]. Journal of Geotechnical and Geoenvironmental Engineering,2010, 136(12): 1655-1663.
[23] LESHCHINSKY D, SAN K C. Pseudostatic seismic stability of slopes: Design charts [J]. Journal of Geotechnical and Geoenvironmental Engineering,1994, 120(9): 1514-1532.
