The effect of expansive concrete on the side resistance of sockets in weak rock

Abstract

In situ load tests and theory are used to investigate the effectiveness of expansive concrete on the improvement of side resistance of sockets in weak rock. Two in situ load test databases are used where rock sockets are constructed with normal and expansive concrete. Both databases include the side shear stress-displacement relationships, the rock mass properties and the socket geometry. Using the side shear stress-displacement relationships, the initial shear stiffness, the peak side shear stresses (and the corresponding displacements) and the post-peak reduction in the side shear stresses at a post-peak displacement of 15 mm are determined. Assessment of the load test data, show that variability in side resistance behavior in sockets constructed with expansive concrete is generally lower than those constructed using regular concrete. In particular, assessment of data show sockets with expansive concrete constitute an upper-bound to the peak side shear stress data. The use of expansive concrete, however, does not result in significant improvements in the post-peak behavior of sockets and initial shear stiffness. Lastly, sockets with expansive concrete generally reached peak shear stress at smaller shear displacements.