scholarly journals Researches on the Influence of Blasting of Newly Built Tunnel on the Existing Tunnel Structure with Small Cross Angle

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Xian Du ◽  
Qinghua Xiao ◽  
Congming Li ◽  
Qiang Xiong ◽  
Jianyou Yu
Keyword(s):  
Dynamic Response ◽  
Surrounding Rock ◽  
Vibration Velocity ◽  
Tunnel Structure ◽  
Analytic Hierarchy ◽  
Tunnel Blasting ◽  
Clear Distance ◽  
Highly Correlated ◽  
Correlated Factors ◽  
Hierarchy Process

In recent years, with the increasement of the railway expansion projects, the blasting damage has caused great threat to the safety of the existing tunnel structure. However, few researches are carried out on the influence of tunnel blasting construction on existing small-angle crossing tunnel structure. In this study, the dynamic response of existing tunnel structure to the blasting activities in newly built tunnel is analyzed by numerical simulation. From the comparison of vibration velocity, lining stress, and the displacement of the existing tunnel structure, the blasting methods, surrounding rock condition, cross angle, and clear distance are proven to be the highly correlated factors for the dynamic response of the existing tunnel to blasting. Then, combined with the analytic hierarchy process, the vibration velocity is selected as the optimal index to indicate the dynamic response to blasting activities.

Study on Dynamic Response and Blasting Vibration Monitoring of Small-Distance Tunnels

2011 ◽  
Vol 90-93 ◽  
pp. 2301-2306
Author(s):  
Zheng Guo Zhu ◽  
Ming Lei Sun ◽  
Yong Quan Zhu ◽  
Xing Liang Sun
Keyword(s):  
Dynamic Response ◽  
Small Distance ◽  
Surrounding Rock ◽  
Vibration Monitoring ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Tunnel Blasting ◽  
Metro Tunnel ◽  
Peak Value ◽  
Response Rule

In accordance with characteristics of super-small-distance tunnels in Nanjing metro, the peak value distribution of vibration velocity for existing tunnel was investigated when cut-hole blasted under the conditions of different surrounding rock Grades, followed by dynamic response rule of super-small-distance tunnels blasting. In addition, monitoring emphasis should be placed on upper bench for right tunnel blasting. Therefore, controlled measures of the small-distance tunnels were obtained during construction. Not only is the result fit for the metro tunnel, but it can be as reference for similar engineering.

scholarly journals Risk assessment of geological disasters in Nyingchi, Tibet

2021 ◽  
Vol 13 (1) ◽  
pp. 219-232
Author(s):  
Chenshuang Wu ◽  
Yonggang Guo ◽  
Libin Su
Keyword(s):  
Risk Assessment ◽  
Analytic Hierarchy Process ◽  
Reference Value ◽  
Fuzzy Analytic Hierarchy Process ◽  
Analytic Hierarchy ◽  
Geological Disasters ◽  
Ecological Protection ◽  
Highly Correlated ◽  
Landslides And Debris Flows ◽  
Hierarchy Process

Abstract To reduce the adverse effects of geological disasters on Nyingchi, this article selected nine highly correlated risk assessment factors for the types of geological disasters such as landslides and debris flows and used two methods of analytic hierarchy process and fuzzy analytic hierarchy process for analysis and comparison. The spatial overlay analysis of each factor with weight is carried out in ArcGIS to make a classification map of geological hazards in Nyingchi. Risk assessment of geological disasters such as collapses, landslides, and mudslides indicates that the slope, distance from the faults, and relative elevation difference of topography have severe impact on natural disasters; at least more than 60% of the areas belong to medium-, high-, and extremely high-risk areas, and it is urgent to strengthen protection and governance; the evaluation results of the fuzzy analytic hierarchy process are more in line with the actual survey situation and are more suitable for Tibet. This research is able to provide a basis for ecological protection, ecological restoration, and geological disaster prevention and management in southeastern Tibet. It also has important reference value for the coordinated development of urban and the environmental projects.

scholarly journals Dynamic Response Analysis of Underground Double-Line Tunnel under Surface Blasting

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Pei Zhang ◽  
Jianhua Cai ◽  
Feng Zong ◽  
Yanpeng He ◽  
Qiong Wang
Keyword(s):  
Dynamic Response ◽  
Vibration Velocity ◽  
Response Analysis ◽  
Horizontal Distance ◽  
Height Difference ◽  
Double Line ◽  
Response Characteristics ◽  
Variation Range ◽  
Clear Distance ◽  
Dynamic Response Characteristics

Blasting has been widely used for economical and rapid rock excavation in civil and mining engineering. In order to study the influence of relative horizontal distance and relative vertical distance between two tunnels on the dynamical response of the two tunnels, 10 numerical simulation cases are done by LS-DYNA 3D models under surface explosion by controlling the clear distance and height difference of double-line tunnel, and the ALE multimaterial fluid structure coupling algorithm is applied to analyze the dynamic response characteristics of double-line tunnel under different conditions. The numerical results show that the dynamic response characteristics of the tunnel lining are affected by the change of the clear distance and height difference of the tunnel. With the increase of the height difference between adjacent tunnels, the peak value of vibration velocity at the top of the lining on the blast face increases, which is due to the upward elevation of the right tunnel, which is more conducive to the reflection and superposition of stress waves. When the height difference of tunnel is 4–6 m, the vibration velocity and displacement of monitoring point C on the back blasting side will change abruptly, and the variation range of vibration velocity is about 25%, while the variation range of displacement is about 60%.

scholarly journals Reasonable Layout of Roadway Based on PSO-AHP Optimization Algorithm Under Three-Dimensional Stress Field

2021 ◽  
Author(s):  
Hongbao Zhao ◽  
Hui Cheng ◽  
Chi Zhang ◽  
Yixiao Zhang
Keyword(s):  
Stress Field ◽  
Optimization Algorithm ◽  
Three Dimensional ◽  
Surrounding Rock ◽  
Deviatoric Stress ◽  
Analytic Hierarchy ◽  
Working Face ◽  
Dip Angle ◽  
The Stability ◽  
Hierarchy Process

Abstract Reasonable roadway layout is the fundamental measure to reduce the difficulty of roadway support and improve the stability of surrounding rock. The particle swarm optimization and analytic hierarchy process (PSO-AHP) algorithm of reasonable layout of roadway under the three-dimensional field was proposed, and an engineering verification was carried out in Weijiadi coal mine. The results showed that, The dip angle α1 and azimuth angle α2 affect the distribution of the deviatoric stress of the roadway surrounding rock. Under different stress field, the sensitivity of surrounding rock to α1 and α2 are different. Changing the more sensitive layout parameters can minimize the deviatoric stress and improve the stability of roadway. The PSO-AHP optimization algorithm takes the deviatoric stress as the index to calculate the layout parameters of different parts of the roadway, and then determines the optimal layout parameters through the evaluation function. The roadway of 1104 working face was arranged with the optimal parameters obtained by PSO-AHP optimization algorithm. Compared with the original layout scheme, the deviatoric stress of surrounding rock was reduced and the position of maximum deviatoric stress is transferred. The optimum layout of roadway was combined with an asymmetric support which had a good application effect.

Small Spacing Tunnels the Blasting Excavation Dynamic Effect

2013 ◽  
Vol 353-356 ◽  
pp. 1484-1489
Author(s):  
You Mo ◽  
Bin Teng ◽  
Zu Yin Zou ◽  
Lin Li ◽  
Mei Zhong
Keyword(s):  
Peak Velocity ◽  
Dynamic Effect ◽  
Element Model ◽  
Euler Method ◽  
Vibration Velocity ◽  
Back Side ◽  
Blasting Excavation ◽  
Tunnel Blasting ◽  
Clear Distance ◽  
Small Spacing

Kinetic research of Small spacing tunnel blasting excavation is always the hot issue both at home and abroad. In this paper, the entrance section of a small spacing tunnel is chose as an example, the Explicit dynamic finite element model and the Euler method is adopted to accurately simulate the process of blasting vibration, and the peak vibration velocity response of the tunnel is gotten. Studies has shown that, the peak velocity is more sensitive to space change when clear distance is less than 1.5 times of the hole diameter; various depth of tunnel causes different clamping action of surrounding rock, thus has different effects on peak velocity; vibration velocity at head-burst side is 5-8 times more than that at back side, vibration velocity at tunnel waist is 1.98-2.23 times more than that at up side, vibration velocity at tunnel shoulder is 1.68-1.85 times more than that at up side, so the waist position at head-burst side should be given exclusive attention.

The Prediction and Control Research on the Attenuation Law of Blasting Vibration Peak Velocity in Daiyuling Tunnel

2013 ◽  
Vol 838-841 ◽  
pp. 1429-1434
Author(s):  
Hong Lu Fei ◽  
Xing Zhu Zhang ◽  
Zhi Guang Yang
Keyword(s):  
Wave Attenuation ◽  
Soft Rock ◽  
Surrounding Rock ◽  
Blasting Vibration ◽  
Blasting Excavation ◽  
Tunnel Blasting ◽  
Testing Technology ◽  
Control Research ◽  
Clear Distance ◽  
Vibration Tests

In combination with field blasting vibration tests in Daiyuling 2# Tunnel, abundant field monitoring datum have been obtained, in order to predict the strength of blasting vibration and research the control problem about stability of surrounding rock. Through the evaluation on blasting affects of the first excavated tunnel when the last excavated tunnel in the initial stage is into tunnel hole, establish the relationship of blasting vibration disturbing degree both neighborhood tunnels to improve the accuracy. Acoustic testing technology has been adapted to test rock acoustic velocity with blasting from beginning to end. The experimental results show that: (1) rock has a larger effect on attenuation effect in the spread of seismic wave, and blasting is really damage the surrounding rock; (2) regression analysis with the formula reflecting correctly the real situation on the blasting stress wave attenuation; (3) compared with blasting vibration attenuation coefficient both the left tunnel and right tunnel, the blasting vibration damage in soft rock is more than in hard rock; (4) the most dangerous location caused by tunnel blasting excavation is the adjacent tunnel blasting face, and its velocity is 5.8845 cm/s, it is practical and feasible that the clear distance of neighborhood tunnels should keep in 21m.

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