Prediction of Elastic Modulus of Jointed Rock Mass Using Artificial Neural Networks

2008 ◽  
Vol 26 (4) ◽  
pp. 443-452 ◽  
Author(s):  
Vidya Bhushan Maji ◽  
T. G. Sitharam
Author(s):  
Jagan Jayabalan ◽  
Sanjiban Sekhar Roy ◽  
Pijush Samui ◽  
Pradeep Kurup

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.


2010 ◽  
Vol 1 (2) ◽  
pp. 89-112
Author(s):  
T. G. Sitharam ◽  
M. Ramulu ◽  
V. B. Maji

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.


Author(s):  
T. G. Sitharam ◽  
M. Ramulu ◽  
V. B. Maji

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.


2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Jinxing Lai ◽  
Junling Qiu ◽  
Zhihua Feng ◽  
Jianxun Chen ◽  
Haobo Fan

In the past few decades, as a new tool for analysis of the tough geotechnical problems, artificial neural networks (ANNs) have been successfully applied to address a number of engineering problems, including deformation due to tunnelling in various types of rock mass. Unlike the classical regression methods in which a certain form for the approximation function must be presumed, ANNs do not require the complex constitutive models. Additionally, it is traced that the ANN prediction system is one of the most effective ways to predict the rock mass deformation. Furthermore, it could be envisaged that ANNs would be more feasible for the dynamic prediction of displacements in tunnelling in the future, especially if ANN models are combined with other research methods. In this paper, we summarized the state-of-the-art and future research challenges of ANNs on the tunnel deformation prediction. And the application cases as well as the improvement of ANN models were also presented. The presented ANN models can serve as a benchmark for effective prediction of the tunnel deformation with characters of nonlinearity, high parallelism, fault tolerance, learning, and generalization capability.


2020 ◽  
Vol 14 (1) ◽  
pp. 84-97 ◽  
Author(s):  
Rachel Martini ◽  
Jorge Carvalho ◽  
António Arêde ◽  
Humberto Varum

Background: In this study , a methodology based on non-destructive tests was used to characterize historical masonry and later to obtain information regarding the mechanical parameters of these elements. Due to the historical and cultural value that these buildings represent, the maintenance and rehabilitation work are important to maintain the appreciation of history. The preservation of buildings classified as historical-cultural heritage is of social interest, since they are important to the history of society. Considering the research object as a historical building, it is not recommended to use destructive investigative techniques. Objective: This work contributes to the technical-scientific knowledge regarding the characterization of granite masonry based on geophysical, mechanical and neural networks techniques. Methods: The database was built using the GPR (Ground Penetrating Radar) method, sonic and dynamic tests, for the characterization of eight stone masonry walls constructed in a controlled environment. The mechanical characterization was performed with conventional tests of resistance to uniaxial compression, and the elastic modulus was the parameter used as output data of ANNs. Results: For the construction and selection of network architecture, some possible combinations of input data were defined, with variations in the number of hidden layer neurons (5, 10, 15, 20, 25 and 30 nodes), with 122 trained networks. Conclusion: A mechanical characterization tool was developed applying the Artificial Neural Networks (ANN), which may be used in historic granite walls. From all the trained ANNs, based on the errors attributed to the estimated elastic modulus, networks with acceptable errors were selected.


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