Abstract:

A lot of geological hazards and geotechnical engineering failure cases including slope, dam, construct foundation, et al, are caused by soil seepage deformation. However, it is seldom to study the critical condition of clay seepage failure. This paper represents the microprocess of clay failure caused by additional driving pressure, and takes the antipermeability strength as the critical condition for judging clay seepage failure. Firstly, the equipment and method which stimulate the process of clay failure were designed to test the strength. Secondly, 32 undisturbed samples of clay were tested with different thickness, which are from the engineering field of Tieshan industrial park in Guilin, China. With the testing values of 32 samples, it is concluded that the two factors of seepage ways and sample size influence the anti-permeability strength, and the test results are made by statistical analysis of ArcGis. The average value of 15 samples of 2.5 cm thicknesses, 40.8 kPa, is the anti-permeability strength of the engineering field. Finally, by comparing the strength with the seepage water pressure in field, the probability of clay seepage failure to form soil-cave collapse is assessed. Results indicate that there is a low susceptibility to the formation of subsidence sinkholes under current conditions, as the seepage water pressure is less than the anti-permeability strength in field. By the field investigation, the assessment result is consistent with the truth.

Key words: clay, seepage failure, anti-permeability strength, critical condition