Estimation of rock mass deformation modulus and strength of jointed hard rock masses using the GSI system

Flashcards about the rock mass deformation modulus.

What is required for many applications in rock engineering practice, including excavation and support design?

Rock mass characterization

What parameters are necessary for numerical modeling in rock engineering?

Deformation moduli and strength parameters

What systems are used to classify rock mass?

RQD, Rock Mass Rating, Q and Geological Strength Index (GSI) systems

Which rock mass classification system is directly linked to engineering parameters?

The GSI system

What two factors does the GSI system concentrate on for rock mass description?

Structure and block surface conditions

What parameters are used to quantify the GSI system parameters to better classify jointed rock masses?

Block volume and a joint condition factor

The newly developed quantitative approach for GSI is built on the linkage between descriptive geological terms and measurable field _.

parameters

What is the Point Estimate Method (PEM) implemented for?

To approximate the mean and variance of the mechanical properties of jointed rock masses

What two types of strength criteria are widely used in rock engineering?

Mohr–Coulomb and Hoek–Brown failure criteria

What three properties of the rock mass have to be estimated to apply the Hoek–Brown criterion for estimating the strength of jointed rock masses?

The uniaxial compressive strength of the intact rock, the value of the Hoek–Brown constant mi for the intact rock, and the value of GSI for the rock mass.

What is the range of the GSI value?

0 to 100

What does the D factor depend on?

The degree of disturbance to which the rock mass has been subjected by blast damage and stress relaxation

What parameters are required for a rock mass classification system to group the rock mass and provide rock mass strength and deformation property estimates?

Inherent parameters

List the inherent parameters of rock mass classification.

Parameters of intact rock, joints, and faults

What parameters are needed in a design process, employing numerical analysis?

Rock mass deformation modulus and strength

The GSI system uses only a _ set of parameters to characterize a rock mass.

finite

What is block size an indicator of?

Rock mass quality

Block size is a _ expression of joint density.

volumetric

What three factors define the joint surface condition?

Roughness, weathering, and infilling condition

What does the joint condition factor, JC, quantify?

The joint surface condition