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Showing 3 results for Jointed Rock

Mahin Roosta R., Sadaghyani M.h., Pak A.,
Volume 3, Issue 3 (9-2005)

Existence of discontinuities causes higher deformability and lower strength in rock masses. Thus joints can change the rock mass behaviour due to the applied loads. For this reason properties and orientation of the joint sets have a great effect on the stability of rock slopes. In this paper, after introducing some numerical methods for evaluating the factor of safety for the stability of slopes, stability of jointed rock slopes in the plane strain condition is investigated with the strength reduction technique this method is modified and applied in the multilaminate framework. First of all, stability of one homogeneous rock slope is investigated and compared with the limit equilibrium method. Then stability of a layered rock slope is analyzed with some modifications in the strength reduction technique. Effects of orientation, tensile strength and dilation of layered joint sets on the factor of safety and location of the sliding block are explained.
S.a. Sadrnejad,
Volume 4, Issue 2 (6-2006)

An important concern in rock mechanics is non-homogeneity as joints or fault. Adopting the joints as fractures, fractures are well known for their effects on the mechanical and transport properties of rock. It has been postulated that through fractured/jointed rock, mainly, the polygons turned to the shear vector (ti) are involved in the mobilization of shear resistance. Consequently, in order to locate the contact areas implicated into the shear-test it was firstly necessary to fix the shear direction. Moreover, since laboratory observations clearly show that only the steepest polygon surfaces touch the other sample, the identification of the potential sliding areas only requires the determination of the polygons which are faced to the shear direction and which, among them, are steep enough to be involved. The methodology to be discussed here is modeling of slip on the local and global levels due to the distribution of deformation procedure of the rock joint. Upon the presented methodology, more attention has been given to slip initiation and propagation through rock joint. In particular, softening in non-linear behaviour of joint in going from the peak to residual strengths imparts a behaviour often associated with progressive failure. A multi-plane based model is developed and used to compute plastic strain distribution and failure mechanism of rock joints. Validity of the presented model was examined by comparing numerical and test results showing the behavior of both homogeneous and jointed rock samples under general stress conditions.
H. Shahnazari, M. Esmaeili, H. Hosseini Ranjbar,
Volume 8, Issue 2 (6-2010)

Considerations on the explosion resistant design of special infrastructures have increased in the recent

years. Amongst the various types of infrastructures, road and railway tunnels have a unique importance due to their

vital role in connection routes in emergency conditions. In this study, the explosion effects of a projectile impacting on

a railway tunnel located in a jointed rock medium has been simulated using 2D DEM code. Primarily, a GP2000

projectile has been considered as a usual projectile and its penetration depth plus its crater diameter were calculated

in rock mass. The blast pressure was, then, calculated via empirical formula and applied on the boundary of crater as

input load. Finally, the wave pressure propagation through the jointed rock medium was investigated. In part of the

study a sensitivity analysis has been carried out on jointed rock parameters such as joint orientation, dynamic modulus

and damping ratio. Their effects on tunnel lining axial force as well as bending moment have also been investigated.

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