scholarly journals Mechanical Responses to Different Excavation Methods of Qichongcun Tunnel in Guiyang City, China

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Siwei Xie ◽  
Feng Huang ◽  
Guihe Wang ◽  
Chaoyang Zhu ◽  
Yunji Su ◽  
...  
Keyword(s):  
Strain Field ◽  
Dynamic Balance ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
The Other ◽  
Stress And Strain ◽  
Step Method ◽  
Mechanical Responses ◽  
Secondary Lining ◽  
Guiyang City

The construction method of tunnel has a critical impact on the stress and strain field during excavation. This study simulated the construction of Qichongcun tunnel by applying a different excavation method, including double-sided method, single-sided method, and three-step dynamic balance excavation method. The distribution and variation of the stress, vertical displacement, horizontal displacement of surrounding rocks, and stress of initial and secondary lining were studied. The results showed that large displacement of surrounding rocks would be induced during the construction in three-step method, but the stress of the second lining was small after completion of the construction. The displacement and stress of the three-step dynamic balance excavation method were larger than those of the other two methods, but it still met the requirements of safety.

3D FEM Analysis of Effects on Adjacent Pipelines by Pit Excavation

2011 ◽  
Vol 90-93 ◽  
pp. 165-171
Author(s):  
Qun Lu ◽  
Hui Xia Li ◽  
Jian Bo Yuan
Keyword(s):  
Fem Analysis ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
The Other ◽  
Friction Contact ◽  
3D Fem ◽  
Underground Pipelines ◽  
Symmetric Plane ◽  
Stress And Deformation ◽  
Tension Fracture

Pit excavation influences the stress and deformation of adjacent underground pipelines seriously. On the base of former study, the project was analyzed with the aid of general finite element soft ABAQUS, in which the interactive action of soil with pipeline and pit protection structure were taken into account. Wall-soil friction and pipeline-soil friction contact were used. The influence on adjacent pipelines of pit excavation was analyzed. The laws of deformation and the stress were gained. The results showed that the horizontal displacement was much bigger than the vertical displacement, and the pipeline would lift at the end close to the symmetric plane and fall at the other end. The displacement would decrease with the increment of the distance between pit and pipelines. The laws of influence of the pipeline’s embedment and wall-soil friction were similar, while the latter’s influence was greater than the former’s. The influence on horizontal displacement aroused by wall-soil friction was greater. The principle tensile stress mainly aroused by the pipeline’s horizontal displacement would cause tension fracture. The sections of the pipeline around the area of the end and the middle of the pit were dangerous, which should be particularly protected.

scholarly journals Influence of rigidity of retainers on dynamic behavior of implant-supported removable partial dentures

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Toshifumi Nogawa ◽  
Masayasu Saito ◽  
Naomichi Murashima ◽  
Yoshiyuki Takayama ◽  
Atsuro Yokoyama
Keyword(s):  
Dynamic Behavior ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Denture Base ◽  
Second Molar ◽  
Mechanical Simulation ◽  
Computed Tomography Images ◽  
Significant Difference ◽  
Abutment Teeth ◽  
Distal Extension

Abstract Background Implant-supported removable partial dentures (ISRPDs) are an effective treatment for partially edentulous patients. ISRPDs improve patients’ satisfaction and oral function to a greater extent than RPDs by improving denture stability and enhancing support. However, the effect of a type of direct retainer on displacement of the abutment teeth and dentures in ISRPDs remains unclear. Therefore, we made a resin mandibular model of unilateral mandibular distal-extension partial edentulism for mechanical simulation and compared the dynamic behavior of the abutment teeth and the denture base among different tooth-borne retainers with various rigidities for RPDs and ISRPDs. Methods A resin mandibular model for mechanical simulation that had unilateral mandibular distal-extension edentulism and was missing the first molar, second molar, first premolar, and second premolar, and a denture fabricated from the patient’s computed tomography images were used. Three types of direct retainers with different connecting rigidities were evaluated. The vertical displacement of the denture base and buccal and lingual sides and the mesial displacement of the abutment teeth were measured. Results Regardless of the rigidity of the direct retainers and loading positions, the displacement of the denture bases in the ISRPDs was significantly smaller than that in the RPDs (P < 0.001). There was no significant difference in vertical displacement of the denture bases among direct retainers with various connecting rigidities in the ISRPDs. Conversely, horizontal displacement of the abutment teeth in both the RPDs and ISRPDs tended to be larger with the cone crown telescope, which has high rigidity, than with the cast cingulum rest and wire clasp, which have much lower rigidities. Conclusion Our results suggested that cast cingulum rest and wire clasps as direct retainers are appropriate ISRPDs to minimize denture movement and suppress displacement of the remaining teeth in patients with unilateral mandibular distal-extension partial edentulism.

The Cedar Mountain, Nevada, earthquake of December 20, 1932*

1934 ◽  
Vol 24 (4) ◽  
pp. 345-384 ◽  
Author(s):  
Vincent P. Gianella ◽  
Eugene Callaghan
Keyword(s):  
Sierra Nevada ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Relative Movement ◽  
East Side ◽  
Owens Valley ◽  
The West ◽  
Horizontal Movement ◽  
San Andreas

Summary The Cedar Mountain, Nevada, earthquake took place at about 10h 10m 04s p.m., December 20, 1932. It was preceded by a foreshock noted locally and followed by thousands of aftershocks, which were reported as still continuing in January 1934. No lives were lost and there was very little damage. The earthquake originated in southwest central Nevada, east of Mina. A belt of rifts or faults in echelon lies in the valley between Gabbs Valley Range and Pilot Mountains on the west and Cedar Mountain and Paradise Range on the east. The length of this belt is thirty-eight miles in a northwesterly direction, and the width ranges from four to nine miles. The rifts consist of zones of fissures which commonly reveal vertical displacement and in a number of places show horizontal displacement. The length of the rifts ranges from a few hundred feet to nearly four miles, and the width may be as much as 400 feet. The actual as well as indicated horizontal displacement is represented by a relative southward movement of the east side of each rift. The echelon pattern of the rifts within the rift area indicates that the relative movement of the adjoining mountain masses is the same. The direction of relative horizontal movement corresponds to that along the east front of the Sierra Nevada at Owens Valley and on the San Andreas rift.

scholarly journals Comparison of Dynamic Characteristics between Small and Super-Large Diameter Cross-River Twin Tunnels under Train Vibration

2021 ◽  
Vol 11 (16) ◽  
pp. 7577
Author(s):  
Lin Wu ◽  
Xiedong Zhang ◽  
Wei Wang ◽  
Xiancong Meng ◽  
Hong Guo
Keyword(s):  
Dynamic Characteristics ◽  
Large Diameter ◽  
Horizontal Displacement ◽  
Element Model ◽  
Vertical Displacement ◽  
Decisive Factor ◽  
Cross River ◽  
Static Responses ◽  
Train Vibration ◽  
Twin Tunnels

Train vibration from closely aligned adjacent tunnels could cause safety concerns, especially given the soaring size of the tunnel diameter. This paper established a two-dimensional discrete element model (DEM) of small (d = 6.2 m) and super-large (D = 15.2 m) diameter cross-river twin tunnels and discussed the dynamic characteristics of adjacent tunnels during the vibration of a train that runs through the tunnel at a speed of 120 km/h. Results in the D tunnel showed that the horizontal walls have the same horizontal displacement (DH) and the vertical walls have the same vertical displacement (DV). The stress state of the surroundings of the D tunnel is the decisive factor for DH, and the distance from the vibration point to the measurement point is the decisive factor for DV. Results in the comparison of the d and D tunnels showed that the D tunnel is more stable than the d tunnel with respect to two aspects: the time the tunnel reaches the equilibrium state and the vibration amplitude of the structure’s dynamic and static responses. The dynamic characteristic of the d and D tunnel is significantly different. This research is expected to guide the design and construction of large diameter twin tunnels.

scholarly journals The Gujarat, West India, earthquake (Jan 26th 2001). A geodynamic event in an intraplate compressional regime?

2001 ◽  
Vol 34 (4) ◽  
pp. 1405
Author(s):  
Γ. Δ. ΔΑΝΑΜΟΣ ◽  
Ε. Λ. ΛΕΚΚΑΣ ◽  
Σ. Γ. ΛΟΖΙΟΣ
Keyword(s):  
Large Scale ◽  
Lateral Displacement ◽  
Indian Subcontinent ◽  
Plate Boundary ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Lateral Spreading ◽  
Tectonic Deformation ◽  
Epicentral Area ◽  
Surface Ruptures

The Jan. 26, 2001, Ms=7.7 earthquake occurred in Gujarat region of W. India, which lies 200-400 Km away from the active plate boundary zone, between the Indian subcontinent and the Asian plate, along the India-Pakistan border and the Himalayan belt. An Ms=7.7±0.2 earthquake also occurred in the same region in 1819. A zone of co-seismic E-W surface ruptures, 30-40 Km long and 15-20 Km wide, observed near the epicentral area and seems to be associated with pre-existing reverse faults and thrust folds, which were partially reactivated during the recent earthquake. Except the reverse vertical displacement a significant right lateral displacement was also observed along these E-W surface ruptures. This Ms=7.7 seismic event has been also accompanied by a large scale flexural-slip folding, as the absence of significant co-seismic fault displacement and fault scarp shows. This type of compressional tectonic deformation is also confirmed by the focal mechanism of the earthquake and the seismo-tectonic "history" of the area. The NW-SE open cracks, also observed along the same zone, are associated with the right lateral horizontal displacement of the reactivated fault (or branch faults) and the development of local extensional stress field in the huge anticlinic hinges of the co-seismic flexural-slip folds. A large number of ground ruptures, failures and open cracks are also associated with extensive sand boils, liquefaction phenomena and lateral spreading.

Stress and Deformation Characteristics of Rock-Fill Dam with Asphalt Concrete Core Wall Founded on Deep Overburden

2013 ◽  
Vol 405-408 ◽  
pp. 428-433
Author(s):  
Fu Yong Chu ◽  
Jun Gao Zhu
Keyword(s):  
Yield Surface ◽  
Asphalt Concrete ◽  
Water Storage ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Surface Model ◽  
Concrete Core ◽  
Rock Fill ◽  
Stress And Deformation ◽  
Double Yield

Abstract: The stress and deformation of rock-fill dam with asphalt concrete core wall founded on deep overburden is calculated and analyzed by Duncan E-ν model and double-yield-surface model through three-dimensional finite element method. The stress and deformation of dams in water storage period is compared by the two models, the results show that the deformation distribution of dam core via two different models are coincide one another. The horizontal displacement and vertical displacement of rock-fill dam with asphalt concrete core wall by double-yield-surface model is smaller than which by Duncan E-ν model in the period of water storage. Furthermore, the horizontal displacement and vertical displacement by double-yield-surface model, which are close to the practical test data through the deformation via two models are in good agreement. The analysis of core-wall stress via double-yield-surface model is more reasonable than the Duncan E-ν model. The analysis result of resisting hydraulic fracturing of core dams by DuncanE-ν model is coincide which of core dams by double-yield-surface model.

Study on the Stratum Displacement Changes Caused by the Vertical Shaft Construction in Saturated Ultra Soft Soil

2012 ◽  
Vol 170-173 ◽  
pp. 1005-1012
Author(s):  
Lin You Pan ◽  
Xiao Bing Li ◽  
Chuang Yu ◽  
Fu Xue Sun
Keyword(s):  
Soft Soil ◽  
Field Tests ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Soil Disturbance ◽  
Soil Parameters ◽  
Finite Element Software ◽  
Total Displacement ◽  
Calculation Results ◽  
Engineering Information

In view of Wenzhou saturated super soft soil, This article studied the influence of different soil parameters for the shaft excavation construction and the stratum displacement change law by using Plaxis finite element software, according to the data obtained in field tests. The considered factors included the lateral brace stiffness, the stiffness of the underground diaphragm wall, and the surrounding soil disturbance. The calculation results provided much important engineering information, such as the horizontal displacement nephogram, the vertical displacement nephogram and the total displacement incremental vector diagram of each construction steps, which can be referred for the construction of the similar underground projects in soft soil areas.

Mutual influence of long-span urban highway tunnel and rail transit construction

2021 ◽  
pp. 1-15
Author(s):  
Honglin Yu ◽  
Shiyang Liu ◽  
Chun Zheng ◽  
Yun Li ◽  
Jie Liu
Keyword(s):  
Mutual Influence ◽  
Vertical Displacement ◽  
Relative Displacement ◽  
Urban Rail Transit ◽  
Rail Transit ◽  
Railway Line ◽  
Long Span ◽  
Highway Tunnel ◽  
Urban Rail ◽  
Secondary Lining

In order to analyze the mutual influence between the long-span highway tunnel and urban rail transit tunnel that is constructed at proximity, this paper established 3D finite element models based on Chongqing Zengjiayan Tunnel and the Metro Railway Line 9 and Line 10 projects to calculate and analyze the secondary lining stress, distribution and change law of deformation of Zengjiayan Tunnel and the Metro Railway Line Tunnel. The results show that: (1) The main risk of the Zengjiayan Tunnel is that the tunnel body might displace in the excavation and the surrounding rock stress could possibly change. The forces undertaken by the main structure of the cross-section are calculated and analyzed based on the shallow buried tunnel. Accordingly, the horizontal and vertical displacement limit and relative displacement meet the relevant specification; (2) Zengjiayan Tunnel over the lobby of Liyuchi Station, a transitional station of Line 9 and Line 10. The main risk is the displacement of the transitional channel in the excavation and changes in the stress on surrounding rocks, but the risk of self-structure excavation and support is under control.

scholarly journals Analysis of ground deformation based on GPS in Sanshandao gold mine, China

2018 ◽  
Vol 55 (1) ◽  
pp. 7-14
Author(s):  
Fengshan Ma ◽  
Hongyu Gu ◽  
Jie Guo ◽  
Rong Lu
Keyword(s):  
Ground Deformation ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Mining Area ◽  
Tectonic Stress ◽  
Gold Mine ◽  
Motion Patterns ◽  
Metal Mine ◽  
Risk Areas ◽  
Discontinuous Deformation

Sanshandao Gold Mine is the first and largest mine operating below sea level in China. Mining has been practiced in this region for at least 25 years. In recent years, buildings above the mining area have been extensively damaged. GPS (with 315 monitoring points) was used to monitor the ground deformation since 2009. Ground deformation induced by mining is much more complex in metal mine than that in coal mines due to the well-developed joints, high tectonic stress and several intersecting faults. All of the factors are analyzed in this study. The results show that discontinuous deformation has occurred on the surface because of the sliding to F3 (name of fault), and there are two motion patterns of F3 during the mining process. Additionally, joints in rock masses with steep dip angles contribute to the vertical displacement and joints with shallow dip angles contribute to the horizontal displacement. Meanwhile, high tectonic stress dramatically enlarges the scale of ground deformation, especially with respect to the horizontal displacement. This deformation results in a striped formation of compressed and stretched regions. Additionally, high-risk and potential risk areas are identified in this study. Finally, the successive data measured since 2009 can contribute to a deeper understanding of ground deformation in metal mine.

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