INFLUENCE OF NUMBER OF GEOTECHNICAL SAMPLES ON SLOPE RELIABILITY ANALYSIS
WU Zhenjun，TANG Hua，WANG Shuilin，GE Xiurun
(State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China)
Abstract：The number of geotechnical samples is usually limited in engineering practice. Evaluating the influence of sample number on slope reliability analysis so as to ensure the reliability of analysis results is of great importance. Considering unconsolidated-undrained shear strength of slope，the influence of the number of geotechnical samples on slope reliability is analyzed by two ways：(1) Assuming that the variability of parameters is known and statistical uncertainty is considered in slope reliability analysis. (2) A simple method for simulating geotechnical sampling and testing of actual slope is presented. Slope reliability is computed based on different numbers sampling results，and the frequency distribution of failure probability of slope is obtained，so as to determine the required number of geotechnical samples. The analysis results by the two methods show that when the parameter variability is large，a small number of samples is required；and when the parameter variability is small，large number of samples is required，which differs from the results by classical probabilistic methods. Results from the second method also show that：from the view of practical slope design，the required number of samples for the undrained strength with common coefficient of variation ranging from 0.2 to 0.5，is generally between 10 and 15.
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2013, Vol. 32 
