Proposal of Criteria for Hydraulic Fracturing Based on Measured Properties of Rocks and Rock Classification and Their Applicability

Criterion for hydraulic fracturing in rock foundations of embankment dams

Abstract

In this paper, the influenceofthe depth of ponding and the filling rate on hydraulic fracturingofrock foundation is evaluated quantitatively by considering the characteristics of rocks, and the criterion for hydraulic fracturing in rock foundations of embankment dams is proposed. For that purpose, the finite deformation analysis, of which the validity was approved in the companion paper, was used and the failure propagation due to pressure of ponding from the edge of a single fracture was simulated by considering the measured material properties of 297 kindsof rock. As the result, the criterion for hydraulic fracturing was proposed as a chart with non-dimensional parameters, i.e. the ratio between water pressure at hydraulic fracturing and the overburden pressure (γ_wh_c/σ₀), the ratio between filling rate and hydraulic conductivity (v_a/k) and the critical state parameter (M). The effectiveness of the criterion was checked by application to the failure of Teton dam. To make the criterion with applicability for general situation, the extension of criterion to general rock mass was examined by using the mechanical properties deduced from the rock classification.