Application of limit plasticity to the stability of sinkholes
1990; Elsevier BV; Volume: 29; Issue: 3 Linguagem: Inglês
10.1016/0013-7952(90)90051-2
ISSN1872-6917
AutoresEric C. Drumm, William F. Kane, Chun-Joo Yoon,
Tópico(s)Geotechnical Engineering and Underground Structures
ResumoA solution is obtained using classical plasticity theory and the method of characteristics to evaluate the stability of soils adjacent to a cylindrical void. The soil strength contains both cohesive and frictional components, which allows the solution to be used to evaluate the drained stability of residual soils overlying cavitose bedrock. The method yields a lower bound solution for the magnitude of a surface loading required to cause instability of the system, and provides a description of the slip line defining the failure zone. The results are compared in dimensionless terms for various combinations of cavity diameter and overburden thickness. For a given overburden thickness, small cavities are more stable than large cavities. However, for a given cavity diameter, large overburden thicknesses are shown to be more stable than small thicknesses. This is contrary to conventional slope stability where stability generally decreases with increasing height. The difference is attributed to the role of a circumferential stress component in the axisymmetric solution, which may be significant for small-diameter cavities. Equations are suggested for the determinaton of the vertical stress required to generate an instability, and for estimation of the size or surface extent of damage. These results have significance in soil stability analyses in karst terrain and in the construction of deep foundations such as drilled shafts. The improvement of methods to detect and measure voids in soil (Fischer and Canace, 1989) will make this method particularly attractive.
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