<p>The most challenging rock mass conditions in hard rock subsea tunnels are represented bymajor faults/weakness zones. Poor stability weakness zones with large water inflow can be particularly problematic. At the pre-construction investigation stage, geological ...

The paper describes the history of the Q-system that was introduced in 1974, and its later development. The individual parameters are analysed, and their relevance for the natural geological features they seek to simulate, is discussed. It is concluded that ...

The role of classification in rock engineering and design is discussed. It is important to distinguish between characterization, classification and empirical design method. The classification systems used today should, strictly speaking, either be described ...

Three methods of in situ deformation modulus (Em) measurements of rock masses have been described, analysed and compared. The plate jacking (PJT) test, where the deformations are measured by extensometers in drill holes, gives generally the best results. A ...

In this paper three methods of in situ deformation modulus (Em) measurements of rock masses have been described, analysed and compared. The plate jacking (PJT) test, the Goodman jack test and the plate loading test.

The RMi (rock mass index) system applies input of block size, joint characteristics and strength of intact rock to express the uniaxial compressive strength of a rock mass. From practical use in more than 5 years the RMi rock support method has been further ...

The RMi system is based on defined inherent parameters of the rock mass and is obtained by combining the compressive strength of intact rock and a jointing parameter. The jointing parameter represents the main jointing features, namely block volume (or density ...

The Rock Mass index, RMi, has been developed to satisfy a need for a strength characterization of rock masses for use in rock engineering and design. The method gives a measure of the reduction of intact rock strength caused by discontinuities given by RMi ...

An example is shown how systematic application of engineering geological data and construction aspects can be combined to assess the amount of rock support and tunneling progress for a tunnel.

Norwegians have a long tradition in underground work which is clearly exhibited in Oslo. Although a small (500,000 inhabitants) and fairly spacious city, with variable rock quality, the underground is utilised to a large extent. The ever increasing focus on ...