MATHEMATICAL AND COMPUTER MODELING OF STRESS STATE OF THE ROCK MASS AROUND A CIRCULAR OPENING WITH REGARD TO CONTACT RIGID ANCHORS

2021 ◽  
Vol 8 (1) ◽  
pp. 138-143
Author(s):  
A.S. Sammal ◽  
V.K. Nguen ◽  
T.M. Chan
Keyword(s):  
Rock Mass ◽  
Stress State ◽  
Computer Modeling ◽  
Circular Opening ◽  
Mathematical And Computer Modeling

scholarly journals Elastoplastic Analysis of Circular Opening Based on a New Strain-Softening Constitutive Model and Its Engineering Application in Hydraulic Fracturing

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
T. Yang ◽  
Q. S. Ye
Keyword(s):  
Rock Mass ◽  
Constitutive Model ◽  
Hydraulic Fracturing ◽  
Bearing Capacity ◽  
Fracture Zone ◽  
Strain Softening ◽  
Circular Opening ◽  
Elastic Peak ◽  
Load Bearing ◽  
Plastic Model

Constitutive effect is extremely important for the research of the mechanical behavior of surrounding rock in hydraulic fracturing engineering. In this paper, based on the triaxial test results, a new elastic-peak plastic-softening-fracture constitutive model (EPSFM) is proposed by considering the plastic bearing behavior of the rock mass. Then, the closed-form solution of a circular opening is deduced with the nonassociated flow rule under the cavity expansion state. Meanwhile, the parameters of the load-bearing coefficient and brittles coefficient are introduced to describe the plastic bearing capacity and strain-softening degrees of rock masses. When the above two parameters take different values, the new solution of EPSFM can be transformed into a series of traditional solutions obtained based on the elastic-perfectly plastic model (EPM), elastic-brittle plastic model (EBM), elastic-strain-softening model (ESM), and elastic-peak plastic-brittle plastic model (EPBM). Therefore, it can be applied to a wider range of rock masses. In addition, the correctness of the solution is validated by comparing with the traditional solutions. The effect of constitutive relation and parameters on the mechanical response of rock mass is also discussed in detail. The research results show that the fracture zone radii of circular opening presents the characteristic of EBM > EPBM > ESM > EPSFM; otherwise, it is on the contrast for the critical hydraulic pressure at the softening-fracture zone interface; the postpeak failure radii show a linear decrease with the increase of load-bearing coefficients or a nonlinear increase with the increasing brittleness coefficient. This study indicates that the rock mass with a certain plastic bearing capacity is more difficult to be cracked by hydraulic fracturing; the higher the strain-softening degree of rock mass is, the easier it is to be cracked. From a practical point of view, it provides very important theoretical values for determining the fracture range of the borehole and providing a design value of the minimum pumping pressure in hydraulic fracturing engineering.

scholarly journals Time influence of tunnel support on the factor of safety

2020 ◽  
Vol 157 ◽  
pp. 06002
Author(s):  
Ivana Nedevska ◽  
Zlatko Zafirovski ◽  
Slobodan Ognjenovic ◽  
Ivona Nedevska ◽  
Vasko Gacevski
Keyword(s):  
Rock Mass ◽  
Stress State ◽  
Factor Of Safety ◽  
Tunnel Excavation ◽  
Tunnel Support ◽  
Plastic Deformations ◽  
Primary Stress ◽  
Reaction Curve ◽  
State Changes ◽  
The Moment

Before taking any measures to build a tunnel, the rock (soil) is in a primary stress state, which means that the stress state is a function of the thickness of the overburden. At the moment when the measures necessary to excavate a tunnel are taken, the rock state changes from primary to secondary, leading to stress concentration, especially in the tunnel abutments. If the rock is capable of accepting these stresses, a state of equilibrium is reached after certain deformations. Plastic deformations can occur if the stresses are larger than the strength of the rock mass. To avoid excessive deformations or collapse of the rock and the tunnel excavation, it is necessary to place a support. The achieved factor of safety is a function of both the support type and the time when the support is installed. This paper shall present a numerical example of different pressures considered in order to obtain the rock’s reaction curve.

Blasting Methods of Stress State Determination in Rock Mass

2018 ◽  
Vol 54 (4) ◽  
pp. 569-574
Author(s):  
V. N. Tyupin ◽  
T. I. Rubashkina
Keyword(s):  
Rock Mass ◽  
Stress State ◽  
State Determination
Sign in / Sign up

Export Citation Format

Share Document