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.

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.

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.

Vibration Propagation Law in Different Areas of Tunnel Face Caused by Blasting

2015 ◽  
Vol 744-746 ◽  
pp. 1005-1009
Author(s):  
Jian Jun Shi ◽  
Li Xue ◽  
Qi Zhang ◽  
Hai Li Meng
Keyword(s):  
Attenuation Coefficient ◽  
Blasting Vibration ◽  
Tunnel Face ◽  
Attenuation Law ◽  
Geological Conditions ◽  
Propagation Law ◽  
Blasting Excavation ◽  
Attenuation Index ◽  
Vibration Attenuation ◽  
Cutting Zone

According to the position and role of borehole, the tunnel face is divided into three regions undercutting area, auxiliary area and surrounding areas and each region have different blasting vibration attenuation law. Using blasting vibration testing instrument TC-4850, the vibration caused by blasting excavation in different region of Chongqing terminal connecting line tunnel was monitored and analyzed, and the vibration characteristics and attenuation law of different region in tunnel face were gained. The results show that: the maximum blasting vibration value was produced in cutting area of tunnel; using the partial excavation and setting large diameter hollow hole in the cut area can effectively reduce the blasting vibration, and the more the number of hollow hole, the damping effect was more significant; vibration attenuation parameters were different in different blasting area in tunnel face and with the increase of excavation area, the vibration attenuation coefficient was gradually decreased. Vibration attenuation index was determined by the geological conditions, basically unchanged, the value of the auxiliary area was 0.5~0.67 times the cutting zone, the value of the surrounding area was 0.25~0.33 times the cutting zone. When adopting sub-steps and sub-regional excavation in small spacing tunnel of Chongqing area, vibration attenuation coefficient can be valued by cutting areas 110~120, auxiliary area 60~80, surrounding region 30~40 and vibration attenuation index can be valued by cutting area 1.5, auxiliary and surrounding region 1.6.

scholarly journals Research on Dynamic Response of Slopes With Weak Interlayers Under Mining Blasting Vibration

2022 ◽  
Vol 9 ◽  
Author(s):  
Xiaochao Zhang ◽  
Qingwen Yang ◽  
Xiangjun Pei ◽  
Ruifeng Du
Keyword(s):  
Dynamic Response ◽  
Internal Structure ◽  
Explosive Charge ◽  
Blast Loading ◽  
Dynamic Responses ◽  
Internal Dynamic ◽  
Explosive Energy ◽  
Wide Range ◽  
Blasting Excavation ◽  
Weak Interlayer

As blasting technology starts to be used in a wide range of areas, blast loading has led to an increasing number of geological disasters such as slope deformation, collapses, and soil slippage. Slopes with weak interlayers are more likely to be deformed and damaged under the influence of blast loading. It is of great importance to study the evolution for the deformation of slopes with weak interlayers during blasting excavation. This study constructed a slope model with a weak interlayer to investigate the influence of different factors of blasting, including explosive charge, blast radius, blast origin, and multi-hole blasting, on the internal dynamic response. The deformation mechanism of slopes with weak interlayers under the influence of blast loading was analyzed. Test results show that each layer of the model had a different displacement response (uncoordinated dynamic response) to blasting with various factors. Explosive energy and the pattern of dynamic response of each layer varied depending on different settings of blasting factors such as explosive charge, blast radius, blast origin, and detonation initiation method. When the explosive energy produced under the influence of various factors was small, the change in the uncoordinated dynamic response between layers was significant, and the change gradually became less significant as the explosive energy increased. Therefore, this study has proposed the concept of critical explosive energy, and it is speculated that when the explosive energy produced with various factors is less than critical explosive energy, the dynamic response is mainly affected by the internal structure of the slope (property difference induced geologic layers). In other words, the uncoordinated motion of material’s particles in each layer is caused by different limitations and the degree of movement of the particles, which leads to the uncoordinated dynamic response and uncoordinated deformation of each layer. If the explosive energy is greater than the critical value, the dynamic response of each layer is mainly affected by the explosive energy. The differences in the internal structure of the slope are negligible, and the incoordination of dynamic responses between layers gradually weakens and tends to synchronize.

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.

scholarly journals Conceptualization and preliminary study of engineering disturbed rock dynamics

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Heping Xie ◽  
Jianbo Zhu ◽  
Tao Zhou ◽  
Kai Zhang ◽  
Changtai Zhou
Keyword(s):  
Rock Mass ◽  
Dynamic Response ◽  
Dynamic Behavior ◽  
Dynamic Theory ◽  
Disaster Mitigation ◽  
Dynamic Responses ◽  
Rock Masses ◽  
Rock Dynamics ◽  
Blasting Excavation ◽  
Engineering Projects

Abstract Many large engineering projects, e.g., the Sichuan–Tibet Railway, inevitably cross the earthquake active areas and the geology complicated zones, facing the challenges of dynamic disturbances and disasters. In view of this, the conceptualization of engineering disturbed rock dynamics is proposed in this paper, aiming to systematically study the rock dynamic behavior and response subjected to engineering disturbances, to establish the 3D rock dynamic theory, and to develop the disaster prevention and control technical measures. The classification standards of rock loading states based on strain rate are summarized and analyzed. The engineering disturbed rock dynamics is defined as the theoretical and applied science of rock dynamic behaviors, dynamic responses and their superposition caused by dynamic disturbances during engineering construction and operation periods. To achieve the goals of the proposed engineering disturbed rock dynamics, a combined methodology of theoretical analysis, laboratory experiment, numerical simulation and in situ tests is put forward. The associated research scopes are introduced, i.e., experimental and theoretical study of engineering disturbed rock dynamics, wave propagation, attenuation and superposition in rock masses, rock dynamic response of different loading conditions, dynamic response of engineering projects under construction disturbance and disaster mitigation techniques, and dynamic response of major engineering projects under operation disturbance and safety guarantee measures. Some theoretical, experimental and field preliminary studies were performed, including dynamic behavior of disturbed rock at varied depth and strain rates, dynamic response of rock mass subjected to blasting excavation disturbance and dynamic drilling disturbance, and disturbance of rock mass subjected to TBM excavation. Preliminary results showed that the rock masses are significantly disturbed by dynamic disturbances during construction and operation periods of engineering projects. The innovative conceptualization of engineering disturbed rock dynamics and the expected associated outcomes could facilitate establishing the 3D rock dynamic theory and offering theoretical fundamentals and technical guarantees for safety and reliability of the design, construction and operation of modern large engineering.

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