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.

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.

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.

Simulation Research for the Excavation Stability of IV Brittle Rock Based on Vault Settlement Effect

2014 ◽  
Vol 681 ◽  
pp. 209-213
Author(s):  
Ke Ling Liu ◽  
Long Guo
Keyword(s):  
Brittle Rock ◽  
Analysis Tool ◽  
Underground Engineering ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Simulation Research ◽  
Engineering Construction ◽  
Excavation Process ◽  
The Finite Element Analysis ◽  
The Stability

Due to the brittle rock deformation is not obvious, and the destruction process has the features of sudden and concealment, it is often neglected in the field during construction. In this paper, Brittle rock was selected as the research object. Using the vault subsidence as monitoring parameters, the excavation process was simulated in single line tunnel by the finite element analysis tool of ANSYS, we obtain the maximum displacement of brittle rock and stress variation with time. Then the subsidence effect of different buried condition were analyzed, to determine the stability period of IV Brittle surrounding rock. The research results can be used to guide the development of the monitoring standard, in underground engineering construction of the brittle rock.

Analysis of the Surrounding Rock's Stability Based on Fuzzy Comprehensive Evaluation Model

2012 ◽  
Vol 226-228 ◽  
pp. 1390-1395
Author(s):  
Xia Zhong Zheng ◽  
Qiao Ling Chen ◽  
Hua Fei Li ◽  
Peng Fei Shi
Keyword(s):  
Comprehensive Evaluation ◽  
Evaluation Model ◽  
Fuzzy Comprehensive Evaluation ◽  
Surrounding Rock ◽  
Underground Engineering ◽  
Rock Classification ◽  
Engineering Construction ◽  
Comprehensive Evaluation Model ◽  
Hydropower Engineering ◽  
The Stability

In underground engineering construction of water conservancy and hydropower engineering, determining surrounding rock excavation and supporting construction measures and parameters according to the classification of surrounding rock's stability is an effective method. In hydropower engineering field, it made some achievements of surrounding rock classification through the engineering geological mechanics parameters. but there are some problems in the application. After the study, this paper established a fuzzy comprehensive evaluation model to determine the stability of surrounding rock. Practice has proved it to be more reasonable.

scholarly journals Novel Segmented Roadside Plugging-Filling Mining Method and Overlying Rock Mechanical Mechanism Analyses

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2073 ◽  
Author(s):  
Wenqiang Mu ◽  
Lianchong Li ◽  
Zhongping Guo ◽  
Zhaowen Du ◽  
Sixu Wang
Keyword(s):  
Coal Mining ◽  
Surrounding Rock ◽  
Equivalent Model ◽  
Mine Pressure ◽  
Mining Method ◽  
Operation Process ◽  
Geological Conditions ◽  
Pillar Mining ◽  
The Stability ◽  
Site Test

The no-pillar mining method is widely used in coal mining engineering because of its superiority in resolving mine pressure hazards and protecting natural resources. In view of the geological conditions of stable strata in a coal mine of the Shandong Coal Zone, a novel segmented roadside plugging-filling mining method is proposed by introducing the filling coefficient into roadside filling. The operation process is designed with a new grouting filling forming device. Based on the relationship between the theoretical deflection of a cantilever beam and geometric settlement and parallel settlement models, strength formulas applicable to the segmented roadside plugging-filling (SRPF) method at different migration stages are obtained, and the deformation formulas of a roadway toward a rock slab are solved by an elastic equivalent model. Further, the determination procedure of the filling mode under the mining method is clarified. The SRPF method was implemented on a test stope, and the test results indicated that the theoretical deformation produced by the SRPF method was small and can meet the mining requirements. Through on-site test monitoring, the deformation of surrounding rock was 0–160 mm and the filling body under the SRPF method could maintain its own strength and the stability of the surrounding rock. In addition, entire successful mining been completed in the working stope, which further proves the applicability of this method. The backfilling cost of the gob-side filling was reduced by approximately 50%, and the backfilling efficiency was improved in the mine. The description of the novel mining method may provide theoretical and practical guidance for coal mining in similar geological conditions.

Simulation Research for the Excavation Stability of III Brittle Rock Based on Vault Settlement Effect

2014 ◽  
Vol 638-640 ◽  
pp. 817-821
Author(s):  
Long Guo ◽  
Ke Ling Liu
Keyword(s):  
Brittle Rock ◽  
Analysis Tool ◽  
Underground Engineering ◽  
Maximum Displacement ◽  
Element Analysis ◽  
Simulation Research ◽  
Engineering Construction ◽  
Excavation Process ◽  
The Finite Element Analysis ◽  
The Stability

Due to the brittle rock deformation is not obvious, and the destruction process has the features of sudden and concealment, it is often neglected in the field during construction. In this paper, Brittle rock was selected as the research object. Using the vault subsidence as monitoring parameters, the excavation process was simulated in single line tunnel by the finite element analysis tool of ANSYS, we obtain the maximum displacement of brittle rock and stress variation with time. Then the subsidence effect of different buried were analyzed, to determine the stability period of III Brittle surrounding rock. The research results can be used to guide the development of the monitoring standard, in underground engineering construction of the brittle rock.

Numerical Simulation Analysis on Impact of Surface Deformation to the Frame-Shear Wall Structure Caused by Tunnel Excavation

2011 ◽  
Vol 243-249 ◽  
pp. 3606-3611
Author(s):  
Chang Feng Yuan ◽  
Guang Ming Yu ◽  
Qian Qian Zhao ◽  
Jing Bo Zou ◽  
Xiao Ming Guan
Keyword(s):  
Numerical Simulation ◽  
Surface Deformation ◽  
Simulation Analysis ◽  
Axial Strain ◽  
Back Analysis ◽  
Wall Structure ◽  
Ground Settlement ◽  
Underground Engineering ◽  
Engineering Construction ◽  
Deformation Law

Underground engineering construction in the city can not avoid bringing about perturbation on the surrounding rock and soil and then endanger the adjacent buildings’ safety. This paper fixes the data of the ground settlement and moving calculation parameters by doing a back analysis of monitoring data which comes from ground settlement caused by subsurface excavation and combing with other engineering experience. This paper predicts the ground settlement，horizontal moving，horizontal deformation and the distortion of incline and curvatural by using the probability integral method.With the numerical simulation,the paper obtains the displacement, axial strain and structural moment’s deformation law which caused by the frame structure’s settlement.The result will provide technical support for the disaster prevention and reduction of underground engineering.

scholarly journals The Comprehensive Treatment of the Ancient Landslide Deformable Body in the Giant Deep Rock Bedding based on the FLAC Analysis Model

2019 ◽  
Vol 23 (4) ◽  
pp. 303-308
Author(s):  
Hongsheng Zhou ◽  
Yunsheng Wang ◽  
Tong Shen ◽  
Qianqian Feng
Keyword(s):  
Deformable Body ◽  
Back Analysis ◽  
Leading Edge ◽  
Rear Side ◽  
Comprehensive Treatment ◽  
Analysis Model ◽  
Ancient Landslide ◽  
Geological Conditions ◽  
Deep Rock ◽  
The Stability

In previous studies, most of the studies are based on the failure mechanism of the landslide deformable body on tunnel and the safety monitoring and early warning after the completion of the tunnel, while there is less research on tunnel construction. In order to study the comprehensive treatment of the deformable body of the ancient landslide in the giant deep rock bedding better, the treatment of JM tunnel landslide deformable body was selected to carry on the empirical study. After a detailed analysis of the geological characteristics of JM tunnel engineering landslide, the stability analysis of the landslide and the deformation body and the calculation of the thrust value based on the FLAC model were carried out on the basis of the monitoring data. After the construction of the model, the intensity parameters of the slip mass deformation and the sliding zone were obtained from the back analysis. On the basis of the above, the comprehensive treatment scheme for the rear side of the old landslide deformation body was determined, including earthwork cleanup, grading supporting, and the back pressure by abandoning the cleaned earthwork at the leading edge. The study is of great significance to the design of the construction of undercrossing tunnel of landslide under the complicated geological conditions.

scholarly journals Tunnel Back Analysis Based on Differential Evolution Using Stress and Displacement

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Joon-Sang An ◽  
Kyung-Nam Kang ◽  
Ju-Young Choi ◽  
Won-Suh Sung ◽  
Vathna Suy ◽  
...  
Keyword(s):  
Differential Evolution ◽  
Differential Evolution Algorithm ◽  
Back Analysis ◽  
Friction Angle ◽  
Internal Displacement ◽  
Average Error ◽  
Analysis Algorithm ◽  
Evolution Algorithm ◽  
Displacement Based ◽  
The Stability

The stability of tunnels has mainly been evaluated based on displacement. Because displacement due to the excavation process is significant, back analysis of the structure and ground can be performed easily. Recently, the length of a segment-lined tunnel driven by the mechanized tunneling method is increasing. Because the internal displacement of a segment-lined tunnel is trivial, it is difficult to analyze the stability of segment-lined tunnels using the conventional method. This paper proposes a back analysis method using stress and displacement information for a segment-lined tunnel. A differential evolution algorithm was adopted for tunnel back analysis. Back analysis based on the differential evolution algorithm using stress and displacement was established and performed using the finite difference code, FLAC3D, and built-in FISH language. Detailed flowcharts of back analysis based on DEA using both monitored displacement stresses were also suggested. As a preliminary study, the target variables of the back analysis adopted in this study were the elastic modulus, cohesion, and friction angle of the ground. The back analysis based on the monitored displacement is useful when the displacement is significant due to excavation. However, the conventional displacement-based back analysis is unsuitable for a segment-lined tunnel after construction because of its trivial internal displacement since the average error is greater than 32% and the evolutionary calculation is finalized due to the maximum iteration criteria. The average error obtained from the proposed back analysis algorithm using both stress and displacement ranged within approximately 6–8%. This also confirms that the proposed back analysis algorithm is suitable for a segment-lined tunnel.

scholarly journals Study on instability failure mode and monitoring early warning standard of surrounding rock in fully weathered argillaceous sandstone section of large section tunnel

2019 ◽  
Vol 136 ◽  
pp. 04023
Author(s):  
Ming Zhao ◽  
Ke Li ◽  
Hong Yan Guo ◽  
KaiCheng Hua
Keyword(s):  
Limit State ◽  
Stable State ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Large Section ◽  
Rock Stability ◽  
Geological Conditions ◽  
Construction Step ◽  
The Face ◽  
The Stability

Based on the special geological conditions of a tunnel in Qingyuan section of Huizhou-Zhanzhou Expressway, FLAC3d numerical simulation software is used to simulate the rheological properties and instability of surrounding rock in large-section fully weathered sandstone section, and the stability and loss of surrounding rock are analyzed. The deformation of the dome and the face at steady state is analyzed. It is found that: 1) when the surrounding rock is in a stable state, the deformation curve of the dome is smooth. When the surrounding rock of the face is unstable, the front of the face appears ahead. Deformation should be first strengthened on the surrounding rock in front of the face. 2) The arched foot is an important part of the instability of the surrounding rock. In order to prevent the expansion of the collapsed part, the arched part should be reinforced. 3) In order to obtain the limit state of surrounding rock stability, the strength of surrounding rock is reduced, and the strength reduction coefficient corresponding to the displacement sudden point is taken as the safety factor of rock stability around the hole, and the stability safety coefficients of surrounding rock of each construction step are greater than 1.2. 4) The dynamic standard values of deformation control in the whole construction stage are obtained by analyzing the deformation curves of each data monitoring point with time in the corresponding time period of each construction step.

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