scholarly journals A Novel Model Using Virtual State Variables and Bayesian Discriminant Analysis to Classify Surrounding Rock Stability

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jinglai Sun ◽  
Darui Ren ◽  
Yu Song ◽  
Mingyuan Yu ◽  
Zhaofei Chu ◽  
...  
Keyword(s):  
Discriminant Analysis ◽  
Surrounding Rock ◽  
Virtual State ◽  
Test Method ◽  
Ratio Test ◽  
State Variables ◽  
Optimal Dimension ◽  
Rock Stability ◽  
Training Samples ◽  
Bayesian Discriminant Analysis

To accurately classify the stability of surrounding rock masses, a novel method (VSV-BDA) based on virtual state variables (VSVs) and Bayesian discriminant analysis (BDA) is proposed. The factors influencing stability are mapped by an artificial neural network (ANN) capable of recognizing the model of rock mass classification, and the obtained output vector is treated as VSVs, which are verified as obeying a multinormal distribution with equal covariance matrixes by normal distribution testing and constructed statistics. The prediction variance ratio test method is introduced to determine the optimal dimension of the VSVs. The VSV-BDA model is constructed through the use of VSVs and the optimal dimension on the basis of the training samples, which are divided from the collected samples into three situations having different numbers. ANN and BDA models are also constructed based on the same training samples. The predictions by the three models for the testing samples are compared; the results show that the proposed VSV-BDA model has high prediction accuracy and can be applied in practical engineering.

scholarly journals Study on instability failure mode and monitoring early warning standard of surrounding rock in fully weathered argillaceous sandstone section of large section tunnel

2019 ◽  
Vol 136 ◽  
pp. 04023
Author(s):  
Ming Zhao ◽  
Ke Li ◽  
Hong Yan Guo ◽  
KaiCheng Hua
Keyword(s):  
Limit State ◽  
Stable State ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Large Section ◽  
Rock Stability ◽  
Geological Conditions ◽  
Construction Step ◽  
The Face ◽  
The Stability

Based on the special geological conditions of a tunnel in Qingyuan section of Huizhou-Zhanzhou Expressway, FLAC3d numerical simulation software is used to simulate the rheological properties and instability of surrounding rock in large-section fully weathered sandstone section, and the stability and loss of surrounding rock are analyzed. The deformation of the dome and the face at steady state is analyzed. It is found that: 1) when the surrounding rock is in a stable state, the deformation curve of the dome is smooth. When the surrounding rock of the face is unstable, the front of the face appears ahead. Deformation should be first strengthened on the surrounding rock in front of the face. 2) The arched foot is an important part of the instability of the surrounding rock. In order to prevent the expansion of the collapsed part, the arched part should be reinforced. 3) In order to obtain the limit state of surrounding rock stability, the strength of surrounding rock is reduced, and the strength reduction coefficient corresponding to the displacement sudden point is taken as the safety factor of rock stability around the hole, and the stability safety coefficients of surrounding rock of each construction step are greater than 1.2. 4) The dynamic standard values of deformation control in the whole construction stage are obtained by analyzing the deformation curves of each data monitoring point with time in the corresponding time period of each construction step.

Application of ABAQUS in Surrounding Rock Stability Analysis of Shallow Large Cross-Section Tunnel

2015 ◽  
Vol 777 ◽  
pp. 8-12 ◽  
Author(s):  
Lin Zhen Cai ◽  
Cheng Liang Zhang
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Strong Support ◽  
Surrounding Rock ◽  
Tunnel Engineering ◽  
Tunnel Excavation ◽  
Rock Stability ◽  
Rock Bolting ◽  
Excavation Support ◽  
The Stability

HuJiaDi tunnel construction of Dai Gong highway is troublesome, the surrounding-rock mass give priority to full to strong weathering basalt, surrounding rock integrity is poor, weak self-stability of surrounding rock, and tunnel is prone to collapse. In order to reduce disturbance, taking advantage of the ability of rock mass, excavation adopt the method of "more steps, short footage and strong support". The excavation method using three steps excavation, The excavation footage is about 1.2 ~ 1.5 m; The surrounding rock bolting system still produce a large deformation after completion of the first support construction, it shows that the adopted support intensity cannot guarantee the stability of the tunnel engineering. Using ABAQUS to simulate tunnel excavation support, optimizing the support parameters of the tunnel, conducting comparative analysis with Monitoring and Measuring and numerical simulation results, it shows that the displacement - time curves have a certain consistency in numerical simulation of ABAQUS and Monitoring and Measuring.

Application of Catastrophe Theory in Surrounding Rock Stability

2013 ◽  
Vol 712-715 ◽  
pp. 974-978
Author(s):  
Din Ge Kong ◽  
Kai Hu
Keyword(s):  
Catastrophe Theory ◽  
Surrounding Rock ◽  
Underground Engineering ◽  
Rock System ◽  
Instability Problem ◽  
Rock Stability ◽  
Highly Nonlinear ◽  
Practical Engineering ◽  
Simplified Mechanical Model ◽  
Catastrophic Model

Surrounding rock system of underground engineering is highly nonlinear, and there is no unified cognition for its stability criteria. Introduces the basic principle of catastrophe theory, focusing on the cusp catastrophic model, build a simplified mechanical model for the surrounding rock, and the instability of surrounding rock of the cusp catastrophic model is obtained. In practical engineering, it is show that catastrophe theory is an effective method to study the instability problem of the tunnel.

Issues of Typology of Municipal Infrastructure

2020 ◽  
Vol 12 (4-2) ◽  
pp. 291-310
Author(s):  
Tatyana Skripkina ◽  
Keyword(s):  
Discriminant Analysis ◽  
Russian Federation ◽  
Uneven Development ◽  
Infrastructure Development ◽  
Data Imputation ◽  
Training Samples ◽  
The Subject ◽  
The Russian Federation ◽  
High Level ◽  
Multidimensional Statistics

The subject of this work is the uneven development of infrastructure in municipal districts of the Russian Federation. The article presents the author’s method of typology of municipalities by the level of infrastructure development, which allows overcoming the shortcomings of the information base of municipal statistics using the data imputation algorithm. The proposed approach solves the problem of weak population structure using a combination of four methods of multidimensional statistics (cluster analysis, factor analysis, metric multidimensional scaling and discriminant analysis) in the framework of a combination of variational and aggregate concepts of data typology. The idea of the considered method is that if an object falls into the same type as a result of applying different typology methods, then it is a stable representative (“core”) of this type. A set of such objects for each type is used as training samples for discriminant analysis, which allows you to typologize the remaining transition objects using mathematical tools. The methodology was tested on a set of municipal districts of the Russian Federation (in 2018). There are 4 types of municipal districts with high, satisfactory, insufficient and low level of infrastructure development. As of 2018, 89 (5.1%) municipal districts of the Russian Federation have a high level of infrastructure development, 308 (17.6%) – satisfactory, 570 (32.6%) – insufficient, 783 (44.7%) – low. The inverse relationship between the level of infrastructure development of municipal districts and the degree of urbanisation of the territory is shown: the largest number of districts with highly developed infrastructure is located in territories with a significant share of the rural population.

Forecasting Algorithm for Cracked Surrounding Rock Stability in Large Span Multi-arch Tunnel

2011 ◽  
Vol 5 (12) ◽  
pp. 104-110
Author(s):  
WU Mengjun ◽  
ZHANG Yongxing ◽  
LIU Xinrong ◽  
LI Xintong
Keyword(s):  
Surrounding Rock ◽  
Large Span ◽  
Rock Stability

scholarly journals Study on the Instability Characteristics and Bolt Support in Deep Mining Roadways Based on the Surrounding Rock Stability Index: Example of Pansan Coal Mine

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Jucai Chang ◽  
Kai He ◽  
Zhiqiang Yin ◽  
Wanfeng Li ◽  
Shihui Li ◽  
...  
Keyword(s):  
Coal Mine ◽  
Stability Index ◽  
Surrounding Rock ◽  
Full Length ◽  
Control Effect ◽  
Support Design ◽  
Rock Stability ◽  
Working Face ◽  
The Stability ◽  
Bolt Support

In view of the influence of mining stress on the stability of the surrounding rock of inclined roof mining roadways in deep mines, the surrounding rock stability index is defined and solved based on the rock strength criterion and the stress distribution. The mining roadway of the 17102(3) working face of the Pansan Coal Mine is used as the engineering background and example. The surrounding rock’ stabilities under the conditions of no support and bolt support are analyzed according to the surrounding rock’s stability index and the deformation data. The results show that the areas of low wall and high wall instability are 1.68 m2 and 2.12 m2, respectively, and the low wall is more stable than the high wall; the areas of the roof and floor instability are 0.33 m2 and 0.35 m2, respectively, and the roof and floor are more stable than the two sides. During mining, the area of instability greatly increases at first, then decreases to 0, and reaches a maximum value at the peak of the abutment pressure. The stability of the surrounding rock decreases first and then increases. Compared with the end anchoring bolt support, the full-length anchoring bolt support reduces the area of instability to a greater extent, and the full-length anchoring bolt support effect is better. The surrounding rock in the end anchoring zone and the full-length anchoring zone began to deform significantly at 200 m and 150 m from the working face, respectively. This indicates that the control effect of the full-length anchoring bolt support is better and verifies the rationality of the surrounding rock stability index to describe the instability characteristics. This research method can provide a theoretical reference for analysis of the stability characteristics and support design of different cross-section roadways.

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