scholarly journals Probabilistic Design and Optimization for Tunnels considering Measuring Uncertainties

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhirong Jia ◽  
Hongbo Zhao ◽  
Changxing Zhu
Keyword(s):  
Test Data ◽  
Rock Strength ◽  
Triaxial Compression ◽  
Interaction Mechanism ◽  
Essential Property ◽  
Circular Tunnel ◽  
Support Structure ◽  
Support Design ◽  
Reliability Based Design ◽  
Bee Colony

Uncertainty is an essential property of rock mechanics and engineering, which is of great significance to excavation, design, and control of rock engineering. In this study, an innovative framework of the reliability-based design was developed for the rock tunnel under uncertainty. The convergence-confinement method is used to characterize the interaction mechanism between the support structure and surrounding rock mass. Artificial bee colony (ABC) was adopted to solve the optimization problem in the reliability-based design. The probabilistic properties of rock strength and failure envelope were obtained based on the triaxial compression test data using the Bayesian method. The reliability of the tunnel and support structure was evaluated based on the abovementioned probabilistic properties of rock strength using the reliability analysis method. A circular tunnel was used to illustrate the developed framework, and the procedure was presented in detail. The time of rockbolt installed, the thickness of the shotcrete, length of rockbolt, circumferential space, and longitudinal space of rockbolt were determined and met the constraints of reliability index. Results show that the developed framework can consider the uncertainty for support design in the tunnel. It provides a good and promising way to support design considering the uncertainty of test data using the reliability-based design.

Experimental Study on Mechanical Properties of Jurassic Soft Rock in Shajihai Mining Area of Xinjiang

2013 ◽  
Vol 353-356 ◽  
pp. 20-23
Author(s):  
Xiao Lei Wang ◽  
Shun Xi Yan ◽  
Guang Can Zhang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Compression Test ◽  
Mechanical Test ◽  
Triaxial Compression ◽  
Soft Rock ◽  
Mining Area ◽  
Surrounding Rock ◽  
Test Results ◽  
Support Design

According to the problemsof serious deformation of soft rock roadways and lack of system andcomprehensive study on surrounding rock characteristics and failure mechanismin Shajihai mining area, this paper carried out a series of mechanicalexperiments on the characteristics of surrounding rock in this area includinguniaxial compression test, triaxial compression test and water absorption propertiestest. Mechanical test results show that the compressive strength of surroundingrock of roadway is generally low, and mudstone compressive strength is thelargest which is 19.23 MPa, and compressive strength of the minimum is coalwhich is 11.32 MPa under natural condition. However sandstone and mudstone’sability of water absorbing is strong, and coal saturation strength issignificantly greater than that of mudstone and sandstone. Therefore, we shouldmake full use of the strength of coal in roadway layout and support design.

scholarly journals Analysis on the Influence Degree of Deformation Control Factors of Deep-Buried Roadway’s Fractured Surrounding Rock Using Orthogonal Design

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Ke Li ◽  
Weijian Yu ◽  
Youlin Xu ◽  
Ze Zhou ◽  
Mengtang Xu ◽  
...  
Keyword(s):  
Orthogonal Design ◽  
Surrounding Rock ◽  
Row Spacing ◽  
Structure Parameters ◽  
Support Structure ◽  
Support Design ◽  
Multi Index ◽  
Cable Length ◽  
Control Factors ◽  
Influence Degree

It is a complex issue to select the support structure parameters for a deep-buried roadway with fractured surrounding rock; especially when the support structure parameters need to be adjusted, the influence degree of support structure parameters on roadway deformation needs to be determined. The deformation of deep-buried roadway’s fractured surrounding rock development was investigated using multi-index orthoplan in this paper. According to the coal mine field investigation, support structure’s failure often occurs, and some need to be repaired many times. Through the roadway surrounding rock drilling, it was found that the stress of the surrounding rock was relieved, resulting in the cavity and separation of the stratum layer. The two sidewalls’ development and roof fractures are mainly tangential, and the original rock state appears only beyond 6.3∼8.2 m. The length of bolts, the row distance between bolts, the length of cables, and the row distance of U-shaped steel were selected as control factors in the multi-index orthogonal design, and roadway’s deformation values were taken as the test indexes. According to the orthoplan, nine numerical simulation schemes were designed, and FLAC3D was used for establishment. The range analysis method was used to analyze the test results. The results show that the control factors’ influence order on the total deformation of the roadway is as follows: row spacing between U-shaped steel > bolt length > cable length > row spacing between bolts, the influence order on the deformation of the roadway floor is as follows: row spacing between U-shaped steel > row spacing between bolts > bolt length > cable length, same as the left sidewall and right sidewall, and the influence order on the roadway roof’s deformation is as follows: row spacing between U-shaped steel > bolt length = cable length > row spacing between bolts, which provide a reference for the support design of deep-buried roadways with fractured surrounding rock, especially the adjustment of the supporting structure.

A New Approach for Determining In-Situ Rock Strength While Drilling

1996 ◽  
Vol 118 (4) ◽  
pp. 249-255 ◽  
Author(s):  
L. L. Hoberock ◽  
G. J. Bratcher
Keyword(s):  
Field Experiment ◽  
Test Data ◽  
Rock Strength ◽  
New Method ◽  
Drill Bit ◽  
New Approach ◽  
Drilling Data

A new method is developed for determining rock strength while drilling with a tri-cone roller bit. The technique employs the well-known “drill-off” test, using commonly measured drilling data, and does not require knowledge of drill bit parameters. The method was evaluated with drill-off test data collected from the Gas Research Institute’s SFE (staged field experiment) well no. 4 and compared with calculated in-situ compressive rock strengths provided by Hareland (1992). The results indicate that the proposed approach produces reasonable results and is easily implemented.

Spatial Variability Analysis of Soil Properties using Geostatistics

2016 ◽  
pp. 195-226 ◽  
Author(s):  
Anand J Puppala ◽  
Tejo V Bheemasetti ◽  
Haifeng Zou ◽  
Xinbao Yu ◽  
Aravind Pedarla ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Spatial Variability ◽  
Soil Properties ◽  
Test Data ◽  
Strength Parameters ◽  
Variability Analysis ◽  
Reliability Based Design ◽  
Piezocone Penetration Test ◽  
Infrastructure Design ◽  
Exploratory Stage

Spatial variability in soil properties is still in the exploratory stage and, despite of an increase in probabilistic and statistical analysis, many challenges remain in using spatial variability of soil properties in practical designs. This chapter addresses the problem of how to incorporate spatial variability of soil properties by using Geostatistics. Existing researches in variability analysis tend to focus on the distribution of the soil properties, reliability based design and simulation of random fields. However, there is limited evidence that researchers have approached the issue of spatial variability in soil properties. Consequently, the aim of this chapter is to develop a framework for incorporating spatial variability in soil properties in prediction analysis and how it could be applied to infrastructure design. The developed framework is validated by performing spatial variability analysis of soil strength parameters evaluated from the piezocone penetration test data.

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