scholarly journals Safety Threshold Determination for Blasting Vibration of the Lining in Existing Tunnels under Adjacent Tunnel Blasting

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Fei Xue ◽  
Caichu Xia ◽  
Guoliang Li ◽  
Baocheng Jin ◽  
Yongwang He ◽  
...  
Keyword(s):  
Surrounding Rock ◽  
Blasting Vibration ◽  
Vibration Data ◽  
Maximum Charge ◽  
Blasting Excavation ◽  
Tunnel Blasting ◽  
Before And After ◽  
Rock Tunnel ◽  
A Site ◽  
Site Test

The effects of tunnel blast excavation on the lining structures of adjacent tunnels are comprehensively studied for the Xinling highway tunnel project. First, the LS-DYNA software is applied to obtain the characteristics of vibration velocities and dynamic stresses at different positions of the tunnel liner. The results indicate that the maximum peak particle velocity (PPV) is located on the haunch of the lining facing the blasting source and that the PPV and peak tensile stress decrease with the increase in the surrounding rock grade. Second, a site test on blasting vibration is conducted to verify the simulation results. By using regression analysis of the measured vibration data, the calculation method of maximum charge per delay for optimizing blasting excavation under different surrounding rock grades is obtained. Finally, based on the statistical relationship between crack alteration and PPV on the lining before and after blasting, the safety thresholds of PPV for different portions of the tunnel are determined. The recommended safety threshold of PPV is 10 cm/s for intact lining and for B-grade and V-grade linings of the surrounding rock tunnel. However, if the lining crack grade falls between 1A and B, then the recommended safety thresholds of PPV for the III-grade and IV-grade surrounding rock tunnel are 5 cm/s and 6 cm/s, respectively. The threshold PPV proposed in this study has been successfully applied to restrict blast-induced damage during new tunnel excavation of the Xinling tunnel project.

scholarly journals Excavation Method of Reducing Blasting Vibration in Complicated Geological Conditions

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Lixiang Xie ◽  
Wenbo Lu ◽  
Jincai Gu ◽  
Gaohui Wang
Keyword(s):  
Back Analysis ◽  
Blasting Vibration ◽  
Underground Engineering ◽  
Engineering Construction ◽  
Vibration Data ◽  
Geological Conditions ◽  
Blasting Excavation ◽  
The Stability ◽  
Site Test ◽  
Blasting Method

Drilling and blasting method as a common excavation method is widely used in the underground engineering construction. However, in the complicated geological conditions, the path of blasting excavation available has limitation, and then the larger blasting vibration is produced, which influence the stability and safety of the protected structure. To effectively reduce the blasting vibration by optimizing the blasting excavation method, firstly, the site test on blasting vibration is conducted to obtain the blasting vibration data; secondly, the LS-DYNA software is applied to simulate the vibration generated by blasting in site test, based on back analysis on the blasting vibration, the mechanical parameters of the rock mass are obtained, and they are used to simulate six different types of blasting excavation method. According to the analysis on them, the reasonable blasting excavation method is proposed to reduce the blasting vibration which can satisfy the blasting safety regulation.

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.

scholarly journals A Study on Dynamic Response of Tunnel Blasting Beneath Surface Buildings

2021 ◽  
Author(s):  
chen huang ◽  
youyi zhang ◽  
Jun Zhao
Keyword(s):  
Dynamic Response ◽  
Weight Bearing ◽  
Dynamic Responses ◽  
Frame Structure ◽  
Blasting Vibration ◽  
Exterior Wall ◽  
Adjacent Buildings ◽  
Propagation Law ◽  
Blasting Excavation ◽  
Tunnel Blasting

In order to study the dynamic response of adjacent buildings in the process of tunnel blasting excavation, taking Yangjia tunnel blasting through a five-story frame structure residential building as an example, the propagation law of blasting seismic wave was analyzed by using HHT method through on-site blasting monitoring. Then, the ALE algorithm in ANSYS/LS-DYNA software was used to establish a three-dimensional numerical model based on the surrounding rock-cutting section-structure coupling to study the dynamic response of adjacent buildings under the blasting vibration of tunnel. The results show that the HHT analysis method can clearly describe the energy distribution of vibration signals in the time and frequency domain. The energy carried by the blasting vibration signal is corresponding to the detonating section, and the maximum energy appears in the cutting section, which further verifying that the vibration effect caused by the cutting hole blasting is the strongest. In the process of tunnel blasting, the dynamic responses of beams, columns and exterior walls of adjacent buildings are not consistent and show different variation rules along the height direction. In addition, the stress centralization mainly occurs in the exterior wall of the building, the joint of the exterior wall and the column, the joint of the exterior wall and the beam, and the joint of the exterior wall and the floor and other non-weight bearing area, indicating that these parts are more likely to damage and crack in the process of tunnel blasting.

scholarly journals Influence of Small, Clear Distance Cross-Tunnel Blasting Excavation on Existing Tunnel below

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Baofu Duan ◽  
Weizeng Gong ◽  
Guoshan Ta ◽  
Xuxu Yang ◽  
Xuewei Zhang
Keyword(s):  
Cross Section ◽  
Practical Significance ◽  
Blasting Vibration ◽  
Axial Distance ◽  
Tunnel Excavation ◽  
Vibration Effect ◽  
Blasting Excavation ◽  
Tunnel Blasting ◽  
Clear Distance ◽  
The Cross

The vibration effect generated during tunnel excavation can influence or damage adjacent tunnels. Studying and controlling the blasting vibration effect has important theoretical and practical significance, especially for new tunnels. This paper takes the tunnel project of Gao Jiu Lu-Jia Hua Cross Tunnel in Chongqing as the research background and assesses the blasting vibration influence in the up-down cross-tunnel. Onsite monitoring and numerical simulation were used to analyze peak particle velocity (PPV) changes, stress distribution, and crown settlement during the excavation process of Gao Jiu Lu I Tunnel at Jia Hua Tunnel Left Line in the cross-section. Influence laws of blasting excavation in a small, clear distance cross-tunnel on an existing tunnel below were obtained. Results show that new tunnel blasting vibrations exerted the largest influence on the crown of the existing tunnel below in the cross-section. The maximum tensile stress of the secondary lining of the existing tunnel below was mainly concentrated in the crown area. The maximum compressive stress during excavation was concentrated in the crown foot, and the stress value was less than the tensile and compressive strength of the concrete. The loosening of the surrounding rock from blasting excavation of the new tunnel caused secondary settlement of the existing tunnel crown below. The cumulative settlement value at the cross-section of the two tunnels was the largest. With an increase in axial distance from the cross-section of the existing tunnel crown, the settlement value gradually declined and became stable. These research results have reference value for the construction of a small, clear distance cross-tunnel and provide theoretical guidance for similar tunnel excavation projects in the future.

Safety Control of Blasting Construction in New Austrian Metro Tunnel

2012 ◽  
Vol 446-449 ◽  
pp. 2462-2465 ◽  
Author(s):  
Hong De Wang ◽  
Xiu Feng Shen
Keyword(s):  
Regression Analysis ◽  
Vibration Monitoring ◽  
Actual Condition ◽  
Vibration Velocity ◽  
Charge Weight ◽  
Blasting Vibration ◽  
Safety Control ◽  
Blasting Excavation ◽  
Tunnel Blasting ◽  
Metro Tunnel

Abstract. Through the analysis and research on the vibration effect caused by the urban New Austrian (shallow embedded) metro tunnel blasting construction, the main harming effect of the blasting vibration on the surface buildings is summarized. According to the actual condition on the site of blasting construction in No.2 line of Dalian metro tunnel, the reasonable vibration monitoring plan for blasting vibration wave is established. At the same time, by means of the regression analysis about the monitoring results of blasting vibration, the vibration wave’s regression formula are set up, which can expression the correlation among the vibration velocity, the charge weight, the distance between the blasting fountains and the buildings. The results show that the Sadaovsk formula can be use to describe the effect of the metro tunnel blasting construction on the surface buildings accurately and reasonably in this construction segment. This kind of regression analysis method can be use to direct subsequent blasting excavation.

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.

Dynamic Analysis of Tunnel Blasting Excavation Effect on Overpass

2014 ◽  
Vol 971-973 ◽  
pp. 992-996
Author(s):  
Chun Lei Xin ◽  
Bo Gao
Keyword(s):  
Three Dimensional ◽  
Simulation Method ◽  
Vertical Vibration ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Strong Constraint ◽  
Protection Measures ◽  
Blasting Excavation ◽  
Tunnel Blasting ◽  
Complicated Conditions

Although drilling and blasting method is widely used to excavate tunnel structures, it has great effect on adjacent ground structures. In order to find out the influence sphere and features of this construction method on overpass, three-dimensional numerical simulation method was used to analyze the displacement, stress and blasting vibration velocity of overpass. The results show that: (1) Drilling and blasting excavation method can cause differential settlement of stratum and overpass which is above the crown of tunnel. (2) The strong constraint structures of overpass are obviously affected by blasting vibration than other parts. (3) It should be taken extra protection measures at connection points between piers and decks as well as connection points between piers and stratum. (4) Horizontal vibration velocity caused by blasting excavation is lower than vertical vibration velocity. To control the vertical blasting vibration velocity is the essential to control the security of tunnel structure and upper structures. The above results certainly contribute to construct tunnel structures by using drilling and blasting excavation under complicated conditions.

The Tunnel of Small Interval Clip Rock Mechanics Properties Research

2012 ◽  
Vol 170-173 ◽  
pp. 1816-1819
Author(s):  
Ye Min Zhang ◽  
Wen Jian Li ◽  
Jin Cai Li
Keyword(s):  
Surrounding Rock ◽  
Weak Rock ◽  
Small Interval ◽  
Element Analysis ◽  
Highway Tunnel ◽  
Geological Conditions ◽  
Before And After ◽  
Parallel Tunnel ◽  
The Stability ◽  
Rock Tunnel

Abstract. In jiangxi red XiaShan highway tunnel interval for engineering background, the key research different scheme for tunnel construction process between them the mechanical behavior of rock and analyzed. For small interval double hole parallel tunnel between them the complex rock stress state, the finite element analysis software for using the numerical analysis method is buried deep in the condition of small interval period of bias by different construction scheme of tunnel numerical simulation. To meshshotcreting firstly method, CD method, up and down steps method, the construction method of different displacement and deformation of the stability of surrounding rock and the comparative analysis. Analyze the different schemes of before and after the surrounding rock tunnel excavation and supporting structure composed of each other of the unity displacement change rule. Put forward the tunnel between them weak rock the concept, more explicit the engineering geological conditions of weak rock tunnel clip to control surfaces. And on the basis of guidance for engineering construction, in actual construction which has obtained a better effect. The result is of a similar project design and construction to provide the reference and the model.

scholarly journals Experimental Study of Blasting Excavation for Large Cross-Section Tunnel in Horizontal Layered Rock Mass

2021 ◽  
Author(s):  
Jie Mei ◽  
Wanzhi Zhang ◽  
Bangshu Xu ◽  
Yongxue Zhu ◽  
Bingkun Wang
Keyword(s):  
Rock Mass ◽  
Cross Section ◽  
Surrounding Rock ◽  
Large Cross Section ◽  
Large Area ◽  
Layered Rock ◽  
Blasting Excavation ◽  
Tunnel Blasting ◽  
Layered Rock Mass ◽  
Upper Face

Abstract The drilling and blasting method is still the main method in mountain tunnel excavation. For large cross-section tunnel in horizontal layered rock mass, tunnel blasting often causes serious overbreak and underbreak. In this study, blasting excavation tests of tunnel upper face were conducted and failure mechanisms of surrounding rocks with weak beddings and joints were analyzed based on the Panlongshan tunnel. Then, the blasthole pattern, the cut mode, a variety of peripheral holes, the charge structure and the maximum single-hole charge were optimized. Compared with the failure characteristics, overbreak and underbreak, and deformations of surrounding rocks before and after optimization, the latter was better in tunnel contour forming and surrounding rock stability. The results show that after optimization, the large-area separation of vault rock mass is solved, the step-like overbreak of spandrel rock mass is reduced and the large-size rock blocks and underbreak are avoided. The maximum linear overbreak of vault, spandrel, and haunch surrounding rocks is decreased by 42.3%, 53.7% and 45.1%, respectively. The underbreak at the bottom of the upper face is reduced from -111.5 to - 16.5 cm. The average overbreak area is decreased by 61.1%. In addition, the displacements after optimization finally converge to the smaller values. The arch crown settlement and the horizontal convergence of haunch are reduced by about 21.6% and 18.3%, respectively. Furthermore, from the completion of blasting excavation to the stabilization of surrounding rock, it takes less time by using the optimized blasting scheme.

scholarly journals Numerical Simulation of Blast Vibration and Crack Forming Effect of Rock-Anchored Beam Excavation in Deep Underground Caverns

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
XinPing Li ◽  
JunHong Huang ◽  
Yi Luo ◽  
Qian Dong ◽  
YouHua Li ◽  
...  
Keyword(s):  
Rock Mass ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Finite Element Software ◽  
Underground Cavern ◽  
Underground Caverns ◽  
Blasting Excavation

Aiming at surrounding rock damage induced by dynamic disturbance from blasting excavation of rock-anchored beam in rock mass at moderate or far distance in underground cavern, numerical model of different linear charging density and crustal stress in underground cavern is established by adopting dynamic finite element software based on borehole layout, charging, and rock parameter of the actual situation of a certain hydropower station. Through comparison in vibration velocity, contour surface of rock mass excavation, and the crushing extent of excavated rock mass between calculation result and field monitoring, optimum linear charging density of blast hole is determined. Studies are also conducted on rock mass vibration in moderate or far distance to blasting source, the damage of surrounding rock in near-field to blasting source, and crushing degree of excavated rock mass under various in situ stress conditions. Results indicate that, within certain range of in situ stress, the blasting vibration is independent of in situ stress, while when in situ stress is increasing above certain value, the blasting vibration velocity will be increasing and the damage of surrounding rock and the crushing degree of excavated rock mass will be decreasing.

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