Numerical Research on Anisotropy Mechanical Parameters of Fractured Rock Mass

2012 ◽  
Vol 524-527 ◽  
pp. 310-316 ◽  
Author(s):  
Pei Feng Sun ◽  
Tian Hong Yang ◽  
Qing Lei Yu ◽  
Wei Shen
Keyword(s):  
Rock Mass ◽  
Elastic Modulus ◽  
Scale Effects ◽  
Fractured Rock ◽  
Deformation Modulus ◽  
Reference Value ◽  
Fracture Network ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Mechanical Parameters

With ShapeMetriX3D rock non-contact measuring technology, structural planes’ distribution of MiaoGou iron mine slope is got. Then, the Mont-Carlo method is used to create equivalent fracture network, with that scale effects and anisotropic properties of rock mass are studied by RFPA2D, considering different scales and directions in statistical window. The results show that both deformation modulus and the strength of the rock mass’s REV are 2.5 m. Furthermore, the strength ratio of filler to rock (K) and the strength of the rock mass fit the logarithmic relationship in rough, while the elastic modulus ratio of filler to rock (M) and the strength of the rock mass fit the linear relationship in rough. The strength of no joints rock mass is much stronger than three times of the strength of jointed rock mass, but the rock mass elastic modulus of no joints is less than 1.6 times of the elastic modulus of jointed rock mass. The research results are directive and have reference value for the study of anisotropy mechanical parameters of rock mass engineering.

A New Method to Determining the Strength Parameters of Fractured Rock Mass

2014 ◽  
Vol 898 ◽  
pp. 378-382
Author(s):  
Yun Hua Guo ◽  
Wei Shen Zhu
Keyword(s):  
Rock Mass ◽  
Mechanical Response ◽  
Fractured Rock ◽  
Fracture Network ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Constitutive Relationship ◽  
Hydropower Station ◽  
Rock Masses ◽  
Fractured Rock Mass

A Hydropower Station is located in the middle reach of the Dadu River in southwest China. The natural slope angles are generally 40°~65° and the relative elevation drop is more than 600m. Complex different fractures such as faults, dykes and dense fracture zones due to unloading are developed. Many abutment slopes were formed during construction of the abutments. The stability of these steep and high slopes during construction and operation period plays an important role for the safe construction and operation of the hydropower station. According to the statistical distribution of joints and fractures at the construction site, the slope is divided into a number of engineering geological zones. For each zone, a stochastic fracture network and a numerical model which is close to the real state of the fractured rock mass are established by the Monte-Carlo method. The mechanical response of fractured rock masses with different sizes of numerical models is studied using FLAC3D. The REV characteristic scale is identified for rock masses in the slopes with stochastic fracture network. Numerical simulation is performed to obtain the stress-strain curve, the mechanical parameters and the strength of the jointed rock mass in the zone. A constitutive relationship reflecting the mechanical response of the jointed rock mass in the zone is established. The Comparison between the traditional method and the method in this paper has been made at the end.

Stochastic Three-Dimensional Joint Geometry Model and the Properties of REV for a Jointed Rock Mass

2014 ◽  
Vol 1079-1080 ◽  
pp. 266-271
Author(s):  
Wen Hui Tan ◽  
Zhong Hua Sun ◽  
Ning Li ◽  
Xiao Hong Jiang
Keyword(s):  
Rock Mass ◽  
Probability Distributions ◽  
Three Dimensional ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Open Pit ◽  
Mechanical Parameters ◽  
Geometry Model ◽  
Joint Geometry ◽  
3D Network

The lithology of rock mass isnon-homogeneity，anisotropy, andexists size effect. The mechanical parameters of rock mass gotten by engineeringapproaches cannot reflect these properties. Therefore, a newmethod of determining the mechanical parameters of jointed rock mass isproposed: gneiss in Shuichang open-pit mine was selected as a case, thefracture system of the rock mass was measured and analyzed by non-contactmeasuring system of 3GSM and probabilisticmethod,the probability distributions of geometry parameters were analyzed and a 3Djoint geometry model was made by using the program of 3D network modeling.Cubes with different sizes were selected to be tested by tri-axial compressionof numerical simulation with 3DEC based on the 3D network model of joints,thus, the REV and its mechanical parameters were determined, which providedcredible parameters for slope stability analysis.

Intelligent Models Applied to Elastic Modulus of Jointed Rock Mass

2018 ◽  
pp. 1-30 ◽  
Author(s):  
Jagan Jayabalan ◽  
Sanjiban Sekhar Roy ◽  
Pijush Samui ◽  
Pradeep Kurup
Keyword(s):  
Neural Network ◽  
Rock Mass ◽  
Elastic Modulus ◽  
Roughness Parameter ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Artificial Neural Network Ann ◽  
Learning Machine ◽  
Hidden Layer ◽  
Intelligent Models

Elastic Modulus (Ej) of jointed rock mass is a key parameter for deformation analysis of rock mass. This chapter adopts three intelligent models {Extreme Learning Machine (ELM), Minimax Probability Machine Regression (MPMR) and Generalized Regression Neural Network (GRNN)} for determination of Ej of jointed rock mass. MPMR is derived in a probability framework. ELM is the modified version of Single Hidden Layer Feed forward network. GRNN approximates any arbitrary function between the input and output variables. Joint frequency (Jn), joint inclination parameter (n), joint roughness parameter (r), confining pressure (s3) (MPa), and elastic modulus (Ei) (GPa) of intact rock have been taken as inputs of the ELM, GRNN and MPMR models. The output of ELM, GRNN and MPMR is Ej of jointed rock mass. In this study, ELM, GRNN and MPMR have been used as regression techniques. The developed GRNN, ELM and MPMR have been compared with the Artificial Neural Network (ANN) models.

Static and Dynamic Elastic Modulus of Jointed Rock Mass

2010 ◽  
Vol 1 (2) ◽  
pp. 89-112
Author(s):  
T. G. Sitharam ◽  
M. Ramulu ◽  
V. B. Maji
Keyword(s):  
Rock Mass ◽  
Elastic Modulus ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Intact Rock ◽  
Rock Properties ◽  
Dynamic Elastic Modulus ◽  
Joint Factor ◽  
Joint Frequency ◽  
Joint Inclination

In this paper the compressive strength/elastic modulus of the jointed rock mass was estimated as a function of intact rock strength/modulus and joint factor. The joint factor reflects the combined effect of joint frequency, joint inclination and joint strength. Therefore, having known the intact rock properties and the joint factor, jointed rock properties can be estimated. The test results indicated that the rock mass strength decreases with an increase in the joint frequency and a sharp transition was observed from brittle to ductile behaviour with an increase in the number of joints. It was also found that the rocks with planar anisotropy exhibit the highest strength in the direction perpendicular to the anisotropy and the lowest at an inclination of 30o-45o in jointed samples. The anisotropy of the specimen influences the dynamic elastic modulus more than the static elastic modulus. The results were also compared well with the published works of different authors for different type of rocks.

Static and Dynamic Elastic Modulus of Jointed Rock Mass

2012 ◽  
pp. 110-133
Author(s):  
T. G. Sitharam ◽  
M. Ramulu ◽  
V. B. Maji
Keyword(s):  
Rock Mass ◽  
Elastic Modulus ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Intact Rock ◽  
Rock Properties ◽  
Dynamic Elastic Modulus ◽  
Joint Factor ◽  
Joint Frequency ◽  
Joint Inclination

In this paper the compressive strength/elastic modulus of the jointed rock mass was estimated as a function of intact rock strength/modulus and joint factor. The joint factor reflects the combined effect of joint frequency, joint inclination and joint strength. Therefore, having known the intact rock properties and the joint factor, jointed rock properties can be estimated. The test results indicated that the rock mass strength decreases with an increase in the joint frequency and a sharp transition was observed from brittle to ductile behaviour with an increase in the number of joints. It was also found that the rocks with planar anisotropy exhibit the highest strength in the direction perpendicular to the anisotropy and the lowest at an inclination of 30o-45o in jointed samples. The anisotropy of the specimen influences the dynamic elastic modulus more than the static elastic modulus. The results were also compared well with the published works of different authors for different type of rocks.

Research on Preparation of Jointed Rock Mass Samples in Site

2011 ◽  
Vol 90-93 ◽  
pp. 593-596
Author(s):  
Yong Liu ◽  
Chun Sheng Qiao
Keyword(s):  
Rock Mass ◽  
Input Parameter ◽  
Deformation Modulus ◽  
Field Tests ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Isotropic Rock ◽  
Important Input ◽  
Cementing Material

The intensity and deformation characterization of a rock mass is an important input parameter in any analysis of rock mass behavior. Field tests to determine this parameter directly are time consuming, expensive and the reliability of the results of these tests is sometimes questionable. Consequently, several authors have proposed empirical relationships for estimating the value of an isotropic rock mass deformation modulus on the basis of classification schemes. But the result is different by different people. Therefore, A new approaches to the mechanical characterization of jointed rock masses has been studied based on the test of little rock mass sample. But preparation of jointed rock mass samples in site is very difficult. In this paper, a method for collecting, preparing and describing samples with extremely to very closely spaced fractures is described where no cementing material is required.

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