Numerical Investigation on Factors Affecting Stability of Roadway Surrounding Rock with Fractured Roof

2018 ◽  
Vol 37 (4) ◽  
pp. 2373-2385 ◽  
Author(s):  
Ke Ding ◽  
Shitan Gu ◽  
Jiaxing Guo ◽  
Dong Gu ◽  
Zheng Liu ◽  
...  
2011 ◽  
Vol 90-93 ◽  
pp. 74-78 ◽  
Author(s):  
Jun Hu ◽  
Ling Xu ◽  
Nu Wen Xu

Fault is one of the most important factors affecting tunnel instability. As a significant and casual construction of Jinping II hydropower station, when the drain tunnel is excavated at depth of 1600 m, rockbursts and water inrush induced by several huge faults and zone of fracture have restricted the development of the whole construction. In this paper, a progressive failure progress numerical analysis code-RFPA (abbreviated from Rock Failure Process Analysis) is applied to investigate the influence of faults on tunnel instability and damaged zones. Numerical simulation is performed to analyze the stress distribution and wreck regions of the tunnel, and the results are consistent with the phenomena obtained from field observation. Moreover, the effects of fault characteristics and positions on the construction mechanical response are studied in details. Some distribution rules of surrounding rock stress of deep-buried tunnel are summarized to provide the reasonable references to TBM excavation and post-support of the drain tunnel, as well as the design and construction of similar engineering in future.


2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Meng Wang ◽  
Jia-wen Zhou ◽  
An-chi Shi ◽  
Jin-qi Han ◽  
Hai-bo Li

The stability of the surrounding rock masses of underground powerhouses is always emphasized during the construction period. With the general trends toward large-scale, complex geological conditions and the rapid construction progress of underground powerhouses, deformation and failure issues of the surrounding rock mass can emerge, putting the safety of construction and operation in jeopardy and causing enormous economic loss. To solve these problems, an understanding of the origins and key affecting factors is required. Based on domestic large-scale underground powerhouse cases in the past two decades, key factors affecting the deformation and failure of the surrounding rock mass are summarized in this paper. Among these factors, the two most fundamental factors are the rock mass properties and in situ stress, which impart tremendous impacts on surrounding rock mass stability in a number of cases. Excavation is a prerequisite of surrounding rock mass failure and support that is classified as part of the construction process and plays a pivotal role in preventing and arresting deformation and failure. Additionally, the layout and structure of the powerhouse are consequential. The interrelation and interaction of these factors are discussed at the end of this paper. The results can hopefully advance the understanding of the deformation and failure of surrounding rock masses and provide a reference for design and construction with respect to hydroelectric underground powerhouses.


2019 ◽  
Vol 9 (10) ◽  
pp. 2064 ◽  
Author(s):  
Yang Liu ◽  
Yicheng Ye ◽  
Qihu Wang ◽  
Xiaoyun Liu ◽  
Weiqi Wang

By applying the Wavelet Relevance Vector Machine (WRVM) method, this research proposes the loose zone of roadway surrounding rock prediction. Based on the theory of relevance vector machine (RVM), the wavelet function is introduced to replace the original Gauss function as the model kernel function to form the WRVM. Five factors affecting the loose zone of roadway surrounding rock are selected as the model input, and the prediction model of the loose zone of roadway surrounding rock based on WRVM is established. By using cross-validation method, the kernel parameters of three kinds of wavelet relevance vector machines (RVMs) are calculated. By comparing and analyzing the root mean square (RMS) error of the test results of each predictive model, the advantages and accuracy of the model are verified. In practical engineering applications, the average relative prediction errors of the Mexican relevance vector machine, the Morlet relevance vector machine and the difference of Gaussian (DOG) relevance vector machine models are accordingly 4.581%, 4.586% and 4.575%. The square correlation coefficient of the predicted samples is 0.95 > 0.9, which further verifies the accuracy and reliability of the proposed method.


1982 ◽  
Vol 8 ◽  
pp. 71-73
Author(s):  
Peter Klint Jensen

Borehole temperatures have been studied to evaluate the natural temperature field of the geological formations (fig. 37). Formation temperature and time are main factors affecting maturation of source rocks and should, therefore, be compared with maturation measurements. Furthermore, temperature gradients through sedimentary sequences provide information about relationships between their heat conductivities, and this can be used to extrapolate temperatures measured in wells to the surrounding rock masses.


2011 ◽  
Vol 250-253 ◽  
pp. 1192-1195
Author(s):  
Xin Yu Wang ◽  
Zhu Shan Shao ◽  
Yu Ming Cui

During the construction of the deep-buried tunnels, high surrounding rock stress and the rockburst are the important factors affecting the stability of surrounding rock. Xiabandi hydraulic engineering is the key project in Tarim River basin. Due to the deep buried excavation, rockburst is particularly prominent and should be received adequate attention. According to the rockburst practice during construction, numerical analysis is adopted to study the stress characteristics along depth with the same lateral pressure coefficient. Furthermore, the rockburst tendency along the tunnel with different burying depth is investigated. The conclusion is of great value to guide the rockburst control during the tunnel design and construction.


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