Application of Ground Freezing Method in Underground Construction

The goal of this paper is instructing the freezing construction scheme of alluvium of wind well in a mine. Through making scheme, designing cooling system and in-situ measuring frozen wall, succeed experiences of passing the expanded clay seam smoothly were achieved. It is hoped that the practical experiences will be reference to constructing mine in the analogous ground.

Controlled displacement-rate in situ shear tests with pore pressure measurements

Two large-scale in situ shear tests were conducted at a damsite in western Canada. The rock at the site is a Cretaceous shale containing a thin clay seam tentatively identified as a bedding-plane shear zone. The material in this seam is significantly weaker than the intact rock and influences the design of certain features of the dam and structures. In order to provide shear strength data for design, two large blocks of shale were sheared along the clay seam. These tests differed from conventional in situ shear tests in two significant ways: the rate of shear displacement was strictly controlled, and pore pressures (both positive and negative) in the shear zone were carefully monitored throughout the test. This note presents the material properties of the shear zone, describes the test equipment and techniques, and discusses the results obtained. Key words: shear strength, in situ testing, pore pressure, shale.