The paper presents further developments of the boundary element technique for solving three-dimensional problems of piecewise homogeneous elastic media containing multiple cracks of arbitrary non-planar shapes (previous results were reported in [1, 2]). In the developed technique, the elastic fields are represented by integral identities. Triangular elements are used to discretize the boundaries and polynomial (linear and quadratic) approximations of the unknown variables are adopted. In-plane components of the fields and geometrical parameters are arranged in various complex-valued combinations to simplify the integration. No singular integrals are involved since the limit, as the field point approaches the boundary, is taken after the integration. Analytical integration over each element is reduced to that over the contour of the element via application of Cauchy- Pompeiu representation . The collocation method is used to set up the system of linear algebraic equations to find the boundary unknowns. Geoengineering applications of the method are discussed.