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.

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.

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.

scholarly journals Vibration Characteristic of High-Voltage Tower Influenced by Adjacent Tunnel Blasting Construction

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Limin Duan ◽  
Wenshuai Lin ◽  
Jinxing Lai ◽  
Peng Zhang ◽  
Yanbin Luo
Keyword(s):  
High Voltage ◽  
Peak Velocity ◽  
Maximum Velocity ◽  
Field Tests ◽  
Control Measures ◽  
Vibration Velocity ◽  
Measuring Point ◽  
Main Frequency ◽  
Tunnel Blasting ◽  
Tower Foundation

The effects of tunnel blast excavation on the adjacent existing high-voltage tower are comprehensively studied for the Chashan highway tunnel project as a case study. To investigate the effect of blast-induced vibration from the tunnel on the adjacent existing tower, field tests and numerical simulations method were adopted to study the vibration velocity and vibration frequency of the existing tower. Moreover, the relationship between the transverse distance from the detonation center and the peak velocity is discussed in detail. The results showed that the peak velocity of the measuring point in tower foundation increases with the distance between the detonation center and tower foundation approaches, and the maximum velocity is appearing when detonation center is 0 m. Furthermore, the corresponding energy spectrum distributions of the existing tower under the effect of blast induced by vibration is also analyzed, and the main frequency of vertical vibration is generally higher than that of transverse vibration. On combining the peak velocity with the main frequency and the natural frequency of the tower, the safety evaluation of the blasting area is proposed, and the corresponding control measures of blasting vibration are put forward. A guideline for the blast safety zone is proposed based on vibration velocity, main frequency, and the quantity of explosive.

scholarly journals Attenuation model of tunnel blast vibration velocity based on the influence of free surface

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Baoxin Jia ◽  
Linli Zhou ◽  
Jiaojiao Cui ◽  
Hao Chen
Keyword(s):  
Free Surface ◽  
Surface Area ◽  
Operating Conditions ◽  
Vibration Velocity ◽  
Blast Vibration ◽  
Free Surfaces ◽  
Blasting Excavation ◽  
Tunnel Blasting ◽  
Velocity Prediction ◽  
Free Surface Area

AbstractIn tunnel blasting excavation, it is important to clarify the attenuation law of blast wave propagation and predict the blast vibration velocity effectively to ensure safe tunnel construction and protection design. The effects of the free surface area its quantity on the blast vibration velocity are considered, and free surface parameters are introduced to improve the existing blast vibration velocity prediction formula. Based on the Tianhuan railway Daqianshiling tunnel project, field blast vibration monitoring tests are performed to determine changes in the peak blasting vibration velocity based on the blast distance and free surface area. LS-DYNA is used to establish tunnel blasting excavation models under three operating conditions; subsequently, the attenuation law of blast vibration velocity and changes in the vibration response spectrum are analysed. Results show that the free surface area and number of free surfaces enable the blast vibration velocity to be predicted under various operating conditions: a smaller free surface area results in a narrower frequency band range, whereas more free surfaces result in a narrower frequency band range. The improved blast vibration velocity prediction formula is validated using field and numerical test data. It is indicated that the improved formula is applicable to various tunnelling conditions.

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 Prediction of Bench Blasting Vibration on Slope and Safety Threshold of Blasting Vibration Velocity to Undercrossing Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Li He ◽  
Dongwang Zhong ◽  
Yihe Liu ◽  
Kun Song
Keyword(s):  
Element Model ◽  
Surrounding Rock ◽  
Vibration Monitoring ◽  
Vibration Velocity ◽  
Blasting Vibration ◽  
Slope Surface ◽  
Safety Criterion ◽  
Construction Period ◽  
Blasting Excavation ◽  
Blasting Load

The reconstruction and expansion project of oil reserve base often faces the excavation and blasting of the slope and undercrossing tunnel at the same time. Due to the flammable and explosive liquid storage nearby, the tight construction period, and the high requirements of collaborative construction, once the blasting accident occurs, the consequences are unimaginable. To facilitate safe and timely cooperative blasting construction of the slope and undercrossing tunnel, a vibration monitoring test of the slope and tunnel surrounding rock is conducted. The vibration response characteristics of the rock surrounding the slope and tunnel are analyzed, and a mathematical prediction model for the peak particle velocity (PPV) with consideration of the influence of the relative slope gradient (H/D) is established based on dimension analysis theory, which improves the prediction accuracy of PPV at the slope surface. ANSYS/LS-DYNA is used to establish a 3D finite element model for the slope and tunnel, and the dynamic response of the tunnel surrounding rock under blasting load is verified through field monitoring data. A linear statistical relationship between PPV and effective tensile stress (ETS) of the tunnel surrounding rock is established. The PPV safety criterion of the tunnel surrounding rock under blasting load is proposed to be 10 cm/s according to the first strength theory, and hence, the minimum safety distance from the tunnel working face to the slope surface is calculated to be 36 m. Finally, the excavation timing arrangement of the slope and tunnel is proposed, which has been successfully applied to the expansion project, and the construction period has been effectively shortened by 45 days while ensuring construction safety. The research results have great guiding significance to similar cooperative blasting excavation engineering for high slope and adjacent tunnel with safety and efficiency.

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.

scholarly journals A revised numerical model for parachute inflation based on ALE method

2020 ◽  
Vol 71 (06) ◽  
pp. 515-518
Author(s):  
CHEN CHEN ◽  
QILEI GUO ◽  
PENG SUN
Keyword(s):  
Numerical Model ◽  
Calculated Data ◽  
Element Model ◽  
Euler Method ◽  
Inertia Force ◽  
Peak Time ◽  
Modified Model ◽  
Common Problems ◽  
Parachute Inflation ◽  
Opening Load

The parachute inflation process is a typical time-varying, non-linear and fluid-structure coupling problem, especially inairdrop condition. For its complexity, numerical model of the inflation process is a big challenge, and most of the modelsestablished before still have room for improvement. There were two common problems that the first one was ignoranceof inertia force of canopy and line, and the second was that took stretch speed as the initial airdrop speed in modelling.Thus, a modified finite element model for canopy inflation process based on ALE (Arbitrary Lagrange Euler) method wasestablished that the inertia force of canopy and line was taken into consideration and the initial airdrop speed wasestimated and adjusted. The opening load in finite mass situation during deployment-inflation process of C-9 typeparachute was calculated. The result was compared to experimental data and calculated data of unmodified models. Itwas indicated that the opening load and peak time of modified model was the closest to experiment and the snatch loadwas also calculated and confirmed, so that the correctness and rationality of the model was verified. Then the factorinfluence of inertia force and initial airdrop speed was analysed, which provided a reference for parachute numericalmodelling.

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.

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