Data entry and operation of a generalized slope stability computer program are described. The computer program is based on a new approach to formulating and solving the slope stability equilibrium equations. The moment equation as well as the horizontal and vertical equilibrium equations are considered in the model. The purpose of the study was to implement the new approach. The computer program may be used to compute the factor of safety of slip surfaces of arbitrary shape and circular slip surfaces. Effective stress and total stress conditions may be analyzed. Four options are available for computing pore pressures. Both piezometric coordinates and pore-pressure rations may be used. The program contains a routine for entering undrained shear strengths as a function of depth. A pseudo-statical approach is used to simulate earthquake forces. The program contains an approach for solving problems that may involve tension cracks. The tension crack model is presented in terms of effective stress, although total conditions may be analyzed. The model solution yields a depth of tension crack based on the mobilized shear strength parameters and is compatible with the factor of safety. Compatibility is achieved through iteration. Alternatively, if the depth of tension crack is known or estimated, then the fixed value of the depth of tension crack may be entered. The tension crack model may be useful in solving such problems as cut slopes and embankments located on soft foundations susceptible to cracking. The program contains a search routine for locating the most critical slip surface having a minimum factor of safety. The search analysis may be used in conjunction with the tension crack analysis and the pseudo-statical earthquake analysis. Eighteen slope stability examples representing a variety of stability conditions and involving slip surfaces of arbitrary shapes and circular slip surfaces were selected and solved. Solutions obtained from the HOPK-I computer model are compared to solutions obtained from stability models developed by Morgenstern and Price, Bishop, Spencer, Janbu, and Hardin. Results are compared to solutions obtained from the ICES LEASE, KY-BISHOP, REAME, and STABL stability computer programs. Generally, differences between solutions from the HOPK-I model and solutions from the Bishop model were about two percent or less. Differences between solutions from the HOPK-I model and solutions obtained from the models developed by Morgenstern and Price, Spencer, Janbu, and Harding were less than about four percent. The simplified Janbu option of the STABL program and the ordinary method of slices generally yielded solutions some 4 to 12 percent lower than solutions obtained from the HOPK-I program.

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