Comparative Analysis of Ground Settlement Caused by Two Kinds of Tunnel Excavation Method

2015 ◽  
Vol 744-746 ◽  
pp. 948-955
Author(s):  
Chang Feng Yuan ◽  
Hai Bin Hang ◽  
Jin Chao Wang ◽  
Zi Jin Yuan
Keyword(s):  
Growth Stage ◽  
Ground Surface ◽  
Simulation Method ◽  
Soil Mass ◽  
Surface Subsidence ◽  
Construction Technology ◽  
Tunnel Excavation ◽  
Section Method ◽  
Tunnel Design ◽  
The Impact

By Inverse analysis through the actual monitoring data and laboratory test, get physical and mechanical parameters of rock and soil mass, use the numerical simulation method to simulate the surface subsidence process of Qingdao city tunnel ZK1 + 810 ~ ZK2 + 810 interval caused by two tunnel excavation methods (the actual use of up and down the steps method and the planned use of the advancing drift whole section method) and comparatively analysis surface subsidence caused by the two methods of construction. The research results show that the surface subsidence causes by the two kinds of construction technology are experienced four stages, namely the impact in advance stage of rapid growth stage, slow growth stage, subsidence and subsidence stabilization stage; The maximum value of surface subsidence caused by up and down the steps method of excavation is greater than that of the advancing drift whole section method; transverse range of ground surface settlement induced by step excavation is about 2D from both sides of the center line of the tunnel, the horizontal range of surface subsidence in advancing drift under construction is generally about 1.5 D ~ 2 D; longitudinal range of the surface subsidence caused by advancing drift under the construction is smaller than method of up and down the steps. The conclusion provides the technical support for the tunnel design and construction.

The Influence of Underpass on Surface Subsidence Caused by Double-Tube Shield Tunneling

2014 ◽  
Vol 915-916 ◽  
pp. 108-113
Author(s):  
Wei Kai Zong
Keyword(s):  
Simulation Method ◽  
Surface Subsidence ◽  
Channel Width ◽  
Ground Movement ◽  
Shield Tunnel ◽  
Underground Structures ◽  
Shield Tunneling ◽  
Underground Channel ◽  
Underground Passage ◽  
The Impact

Shield construction will cause surface subsidence, and the presence of underground structures above the tunnel has an impact on surface subsidence. Based on this, with the engineering of undercross shield tunnel construction on railway station as background, used numerical simulation method to analyze the effect of surface subsidence of underground passage, and studied the influence of depth and width of underpasses on ground movement induced. The results show that: The impact of the underground passage to the wire surface subsidence caused by the shield cannot be ignored. Surface subsidence caused by double shield will be decreased because of the existence of the underground passage, and that related to the channel depth and width. The greater the depth of underground channel, the greater the surface subsidence; greater the underground channel width, the smaller surface subsidence. Meanwhile, the surface subsidence trough width and the largest settlement scope unrelated to the depth of underground tunnels but the underground channel width, and increases with the increasing of the underpass width.

Optimization Analysis of Different Excavation Offsets in Railway Pilot Tunnel by CRD Method

2014 ◽  
Vol 505-506 ◽  
pp. 134-138
Author(s):  
Chun Kui Li
Keyword(s):  
Production Efficiency ◽  
Ground Surface ◽  
Simulation Method ◽  
Subway Station ◽  
Optimization Analysis ◽  
Tunnel Excavation ◽  
Construction Model ◽  
Surface Settlements ◽  
Stress Variations ◽  
Optimal Construction

This paper focuses on the construction of 10 railway pilot tunnels by CRD method in Jiefang Road subway station in Changchun. To achieve the optimal construction offsets during the pilot tunnel excavation, reduce the impacts of group cavern effect, and maximize the production efficiency, the construction model of railway pilot tunnel in subway station was created by the finite difference software Flac3D. The author used the numerical simulation method to analyze the ground surface settlements and the stress variations with three different construction offsets. Then the optimal construction offset was obtained. It could provide a theoretical guidance to the construction of a similar project.

Analysis of the Ground Surface Settlement of Metro Tunnel by Using Peck Formula

2014 ◽  
Vol 1065-1069 ◽  
pp. 414-420
Author(s):  
Xiong Fei Yang ◽  
Hong Yuan ◽  
Jia Yu Wu ◽  
Hou Mei Zhang
Keyword(s):  
Surface Deformation ◽  
Ground Surface ◽  
Surface Subsidence ◽  
Central Point ◽  
Surface Settlement ◽  
Point Method ◽  
Linear Regression Method ◽  
Tunnel Excavation ◽  
Ground Surface Settlement ◽  
Ground Surface Subsidence

Based on the peck formula, this paper has analyzed measured data of ground surface subsidence, and get the regression curve of ground surface subsidence. Expression for degree of reliability of the maximum ground surface settlement is derived analytically by using central-point method. On the basis of a certain section of tunnel of Guangzhou subway constructed by mining excavation method, linear regression method can be effectively fitting the ground surface deformation data due to tunnel excavation. The central-point method provides a new way for reliability analysis of the ground surface settlement of shield construction.

scholarly journals MODELING OF BLAST EFFECTS ON UNDERGROUND STRUCTURE

2019 ◽  
Vol 15 (4) ◽  
pp. 111-122
Author(s):  
Oleg Mkrtychev ◽  
Anton Savenkov
Keyword(s):  
Shock Wave ◽  
Nonlinear Dynamic ◽  
Underground Structure ◽  
Ground Surface ◽  
Soil Mass ◽  
Point Explosion ◽  
Coupled Numerical Model ◽  
Blast Effects ◽  
Dynamic Formulation ◽  
The Impact

Modeling of the impact of a point explosion shock wave on a soil mass and an underground structure at different locations of the explosion epicenter from the ground surface was performed. The study of the stress- strain state of soils was carried out usi ng a nonlinear dynamic method and a fully coupled numerical model, in­cluding various models of materials. The result of numerical modeling showed the adequacy of the adopted nu­merical calculation methods. The findings showed that solving the problem in a nonlinear dynamic formulation allows obtaining the parameters of the shock wave at different depths from the explosion center, as well as ob­taining a complete picture of the interaction of the shock wave with the underground structure in surface and un­derground explosions.

Stochastic simulation for determining the design flood of cascade reservoir systems

2012 ◽  
Vol 43 (1-2) ◽  
pp. 54-63 ◽  
Author(s):  
Baohong Lu ◽  
Huanghe Gu ◽  
Ziyin Xie ◽  
Jiufu Liu ◽  
Lejun Ma ◽  
...  
Keyword(s):  
Simulation Model ◽  
Stochastic Simulation ◽  
Southern China ◽  
Flow Simulation ◽  
Simulation Method ◽  
Simulation Approach ◽  
Design Flood ◽  
Design Values ◽  
Stochastic Simulation Model ◽  
The Impact

Stochastic simulation is widely applied for estimating the design flood of various hydrosystems. The design flood at a reservoir site should consider the impact of upstream reservoirs, along with any development of hydropower. This paper investigates and applies a stochastic simulation approach for determining the design flood of a complex cascade of reservoirs in the Longtan watershed, southern China. The magnitude of the design flood when the impact of the upstream reservoirs is considered is less than that without considering them. In particular, the stochastic simulation model takes into account both systematic and historical flood records. As the reliability of the frequency analysis increases with more representative samples, it is desirable to incorporate historical flood records, if available, into the stochastic simulation model. This study shows that the design values from the stochastic simulation method with historical flood records are higher than those without historical flood records. The paper demonstrates the advantages of adopting a stochastic flow simulation approach to address design-flood-related issues for a complex cascade reservoir system.

scholarly journals Erosion Transportation Processes as Influenced by Gully Land Consolidation Projects in Highly Managed Small Watersheds in the Loess Hilly–Gully Region, China

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1540
Author(s):  
Qianqian Ji ◽  
Zhe Gao ◽  
Xingyao Li ◽  
Jian’en Gao ◽  
Gen’guang Zhang ◽  
...  
Keyword(s):  
Similarity Theory ◽  
Design Method ◽  
Simulation Method ◽  
Practical Significance ◽  
Land Consolidation ◽  
Small Watershed ◽  
Flood Peak ◽  
Erosion Area ◽  
The Impact ◽  
Erosion Environment

The Loess Hilly–Gully region (LHGR) is the most serious soil erosion area in the world. For the small watershed with high management in this area, the scientific problem that has been paid attention to in recent years is the impact of the land consolidation project on the erosion environment in the gully region. In this study, the 3D simulation method of vegetation, eroded sediment and pollutant transport was innovated based on the principles of erosion sediment dynamics and similarity theory, and the impacts of GLCP were analyzed on the erosion environment at different scales. The verification results show that the design method and the scale conversion relationship (geometric scale: λl = 100) were reasonable and could simulate the transport process on the complex underlying surface of a small watershed. Compared with untreated watersheds, a significant change was the current flood peak lagging behind the sediment peak. There were two important critical values of GLCP impact on the erosion environment. The erosion transport in HMSW had no change when the proportion was less than 0.85%, and increased obviously when it was greater than 3.3%. The above results have important theoretical and practical significance for watershed simulation and land-use management in HMSW.

scholarly journals The Effect of LiDAR Sampling Density on DTM Accuracy for Areas with Heavy Forest Cover

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 265
Author(s):  
Mihnea Cățeanu ◽  
Arcadie Ciubotaru
Keyword(s):  
Forest Cover ◽  
Initial Point ◽  
Ground Surface ◽  
Digital Terrain Model ◽  
Morphological Data ◽  
Sampling Density ◽  
Terrain Model ◽  
Digital Terrain ◽  
Point Density ◽  
The Impact

Laser scanning via LiDAR is a powerful technique for collecting data necessary for Digital Terrain Model (DTM) generation, even in densely forested areas. LiDAR observations located at the ground level can be separated from the initial point cloud and used as input for the generation of a Digital Terrain Model (DTM) via interpolation. This paper proposes a quantitative analysis of the accuracy of DTMs (and derived slope maps) obtained from LiDAR data and is focused on conditions common to most forestry activities (rough, steep terrain with forest cover). Three interpolation algorithms were tested: Inverse Distance Weighted (IDW), Natural Neighbour (NN) and Thin-Plate Spline (TPS). Research was mainly focused on the issue of point data density. To analyze its impact on the quality of ground surface modelling, the density of the filtered data set was artificially lowered (from 0.89 to 0.09 points/m2) by randomly removing point observations in 10% increments. This provides a comprehensive method of evaluating the impact of LiDAR ground point density on DTM accuracy. While the reduction of point density leads to a less accurate DTM in all cases (as expected), the exact pattern varies by algorithm. The accuracy of the LiDAR-derived DTMs is relatively good even when LiDAR sampling density is reduced to 0.40–0.50 points/m2 (50–60 % of the initial point density), as long as a suitable interpolation algorithm is used (as IDW proved to be less resilient to density reductions below approximately 0.60 points/m2). In the case of slope estimation, the pattern is relatively similar, except the difference in accuracy between IDW and the other two algorithms is even more pronounced than in the case of DTM accuracy. Based on this research, we conclude that LiDAR is an adequate method for collecting morphological data necessary for modelling the ground surface, even when the sampling density is significantly reduced.

scholarly journals Sustainability of Extraction of Raw Material by a Combination of Mobile and Stationary Mining Machines and Optimization of Machine Life Cycle

2020 ◽  
Vol 12 (24) ◽  
pp. 10454
Author(s):  
Katarína Teplická ◽  
Martin Straka
Keyword(s):  
Life Cycle ◽  
Raw Materials ◽  
Simulation Method ◽  
Raw Material ◽  
Optimal Distribution ◽  
Transport Costs ◽  
Scientific Discussion ◽  
Mining Companies ◽  
Conveyor Belts ◽  
The Impact

This article summarizes the arguments within the scientific discussion on the issue of using mining machines and their life cycle. The main goal of the article is to investigate the impact of a combination of mobile and stationary mining machines and their optimal distribution in the mining process to increase the efficiency of mining and processing of raw materials. The following methods of research were focused on the use of technical indicators for the valuation efficiency of the mining process: a simulation method was used for the distribution of mining machines, comparison analysis was used for the real and past state of mining machines, and a decision tree was used as managerial instrument for optimal alternatives of mining machines. The research empirically confirms and theoretically proves that optimal distribution of mining machines and machine parks is very important for mining companies. The benefit of this research for the mining company was the new location of the machines and the combination of stationary production lines and mobile equipment. The optimal layout of the machines reduced the number of conveyor belts and improved the transfer of limestone processing to mobile devices, saving time, which was reflected in transport costs. The results can be useful for other mining companies seeking to create an optimal machine park.

scholarly journals THE SAFEST REVIEW: THE SHOCK-ABSORBING FLOORING EFFECTIVENESS SYSTEMATIC REVIEW IN CARE SETTINGS

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S492-S493
Author(s):  
Amy K Drahota ◽  
Bethany E Keenan ◽  
Chantelle Lachance ◽  
Lambert Felix ◽  
James P Raftery ◽  
...  
Keyword(s):  
Systematic Review ◽  
Injury Prevention ◽  
Ground Surface ◽  
Work Related ◽  
Clinical Trial Registries ◽  
Injurious Falls ◽  
Study Selection ◽  
Health And Social Care ◽  
Implementation Studies ◽  
The Impact

Abstract Falls in hospitals and care homes are a major issue of international concern. Falls cost the US $34 billion a year, with injurious falls being particularly life-limiting and costly. Shock-absorbing flooring decreases the stiffness of the ground surface to reduce the impact of a fall. There is a growing body of evidence on flooring for fall-related injury prevention, however no systematic review exists to inform practice. We systematically reviewed the evidence on the clinical and cost-effectiveness of shock-absorbing flooring use for fall-related injury prevention in care settings. We searched six databases, clinical trial registries, conference proceedings, theses/dissertations, websites, reference lists, conducted forward citation searches, and liaised with experts in the field. We conducted study selection, data collection, and critical appraisal independently in duplicate. We evaluated the influence of shock-absorbing flooring on fall-related injuries, falls, and staff work-related injuries. We adopted a mixed methods approach considering evidence from randomised, non-randomised, economic, qualitative, and implementation studies. We assessed and reported the quality of outcomes using the GRADE approach and Summary of Findings Tables. This review, conducted over the course of 2019, summarises the certainty of the evidence on whether and which shock-absorbing floors influence injuries from falls, the chance of someone falling over, and work-related injuries in staff (e.g. from manoeuvring equipment across softer floors). Our findings are applicable to health and social care professionals, buildings and facilities managers, carers, older adults, architects, and designers. Funded by National Institute for Health Research, Health Technology Assessment (ref 17/148/11); registered in PROSPERO (CRD42019118834).

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