An Analysis of Soil Failure by a Subsoiler with Pressurized Fluid Injection (Part 3)

Nonlinear Three-Dimensional Finite Element Analysis of Water Injection Cutting by a Pan-breaker

Abstract

There are two different design objectives for subsoilers with pressurized fluid injection, for use as pan-breakers and injectors respectively. A large soil failure is desirable when it is used as a pan-breaker and little soil failure is advantageous when it is used as an injector. This paper first analysed the water injection cutting by a pan-breaker with finite element method (FEM). The results showed that with 8.6% d. b. soil moisture, a fracture failure took place. Here, the injected water flow rate should be controlled and limited at the minimum where draught reduction can be obtained, because of long soil rupture distances. With 16.3% d. b. soil moisture, a plastic flow took place and the stresses induced in soil layer by pan-breaker-movement were considerbly small and soil rupture distances were limited. Therefore, panbreaker work should be refrained because of a low breaking efficiency.