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| UNIFIED METHOD OF SEPARATE AND COMBINED CALCULATION OF WATER AND EARTH PRESSURES |
| (Shanghai No.2 Municipal Engineering Co.，Ltd.，Shanghai 200065，China) |
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Abstract Applying combined calculation of water and earth pressures for clay leads to a result which is more close to the field measurement value，however，obviously violates the principle of effective stress. Based on characteristics of the pore water in soil，it is assumed that the bound water absorbed by the clay particles in the soil offsets part of soil pore，and finally physical parameters such as void ratio，boundary water content，particle analysis，etc. are introduced to calculation of water and earth pressures on retaining structures to propose a coefficient which can be calculated through physical parameters of soil and to provide the method of measuring the value of through permeability tests. With the coefficient ，the effective stress intensity index and total stress intensity index are integrated in one strength formula. A new calculation method to unify the separate calculation and combined calculation of water and earth pressures is proposed to carry out the transition between results of the two conventional calculation methods and provide a new idea for solving the jump problem between the two results. According to the theory analysis of this paper，the measured permeability coefficient-void ratio curve will have a translational move in a forward direction along e-axis. The more clay particles that soil contains will have the larger translation，which has been verified by experimental data of related literatures. Separate calculation of water and earth pressures is too conventional for sand soil containing clay particles while combined calculation of water and earth pressures for clay with high void ratio can?t guarantee the safety. Water and earth pressures on retaining structure are related not only to the soil categories，but also the void ratio.
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Received: 07 January 2011
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2011, Vol. 30 
