scholarly journals Prediction of Landslide Position of Loose Rock Mass at Mountain Tunnel Exit

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Ya-Qiong Wang ◽  
Cheng-Bin Ma ◽  
Zhi-Feng Wang
Keyword(s):  
Rock Mass ◽  
Prediction Methods ◽  
Tunnel Engineering ◽  
Improved Method ◽  
Engineering Problems ◽  
Calculation Results ◽  
True Position ◽  
Optimal Calculation ◽  
Mountain Tunnel ◽  
Loose Rock

Landslide of loose rock mass at mountain tunnel exit occurs easily, and prediction of landslide position is one of the engineering problems to be solved urgently. Currently, existing and used prediction methods, such as field monitoring measurement, numerical analysis, nonlinear theories, and the geometric method, play a very important role and have their limitations. For example, there is a bigger difference between calculation mode by Wang et al.’s method and actual engineering situation; besides, there exists a relatively big discrepancy between the predicted and true position. Aiming to solve this problem, this article combined theoretical analysis and actual engineering situation to establish an optimal calculation mode. At the same time, this article re-deduced instability criteria based on the stress-transferring theory and examined the factors that influence solutions. The improved method can predict landslide position more accurately because the parameters (β, s, H, α, γ, c, φ, and T) related to the occurrence of landslide are taken into consideration. It is pointed out that landslide possibly occurs in the case of Δ ≥ 0 and Y ≤ 0. In addition, the equations s1 < s < s2 and 0 ≤ s ≤ H/sin α can determine landslide position accurately. The method is applied to two engineering examples, and the calculation results show that the deviations of predictive position from the actual landslide position are only 0.10% and 0.07%, respectively, indicating that prediction results are accurate and reliable. It is suggested that the proposed method is a useful tool in the design of tunnel engineering.

Dynamic Analysis of DVG 850 High-Speed Machining Center

2012 ◽  
Vol 487 ◽  
pp. 203-207
Author(s):  
Gong Xue Zhang ◽  
Xiao Kai Shen
Keyword(s):  
High Speed ◽  
Simulation Analysis ◽  
Response Analysis ◽  
Improved Method ◽  
Analysis Software ◽  
Element Analysis ◽  
Harmonic Response ◽  
Machining Center ◽  
Calculation Results ◽  
Harmonic Response Analysis

Purpose, with the application of workbench finite element analysis software, get the analysis results of DVG 850 high-speed vertical machining center via the modal analysis and harmonic response analysis. Use the calculation results for reference, put forward the improved method, and prove the credibility of the simulation analysis by testing DVG 850 prototype.

Application of ABAQUS in Surrounding Rock Stability Analysis of Shallow Large Cross-Section Tunnel

2015 ◽  
Vol 777 ◽  
pp. 8-12 ◽  
Author(s):  
Lin Zhen Cai ◽  
Cheng Liang Zhang
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Strong Support ◽  
Surrounding Rock ◽  
Tunnel Engineering ◽  
Tunnel Excavation ◽  
Rock Stability ◽  
Rock Bolting ◽  
Excavation Support ◽  
The Stability

HuJiaDi tunnel construction of Dai Gong highway is troublesome, the surrounding-rock mass give priority to full to strong weathering basalt, surrounding rock integrity is poor, weak self-stability of surrounding rock, and tunnel is prone to collapse. In order to reduce disturbance, taking advantage of the ability of rock mass, excavation adopt the method of "more steps, short footage and strong support". The excavation method using three steps excavation, The excavation footage is about 1.2 ~ 1.5 m; The surrounding rock bolting system still produce a large deformation after completion of the first support construction, it shows that the adopted support intensity cannot guarantee the stability of the tunnel engineering. Using ABAQUS to simulate tunnel excavation support, optimizing the support parameters of the tunnel, conducting comparative analysis with Monitoring and Measuring and numerical simulation results, it shows that the displacement - time curves have a certain consistency in numerical simulation of ABAQUS and Monitoring and Measuring.

Why the future of rock mass classification systems requires revisiting their empirical past

2021 ◽  
pp. qjegh2021-039
Author(s):  
Beverly Yang ◽  
Amichai Mitelman ◽  
Davide Elmo ◽  
Doug Stead
Keyword(s):  
Rock Mass ◽  
Rock Mass Classification ◽  
Classification Systems ◽  
Empirical Knowledge ◽  
Rock Engineering ◽  
Geotechnical Data ◽  
Use Of Technology ◽  
Data Collection Process ◽  
Engineering Problems ◽  
Mass Classification

Despite recent efforts, digitisation in rock engineering still suffers from the difficulty in standardising and statistically analysing databases that are created by a process of quantification of qualitative assessments. Indeed, neither digitisation nor digitalisation have to date been used to drive changes to the principles upon which, for example, the geotechnical data collection process is founded, some of which have not changed in several decades. There is an empirical knowledge gap which cannot be bridged by the use of technology alone. In this context, this paper presents the results of what the authors call a rediscovery of rock mass classification systems, and a critical review of their definitions and limitations in helping engineers to integrate these methods and digital acquisition systems. This discussion has significant implications for the use of technology as a tool to directly determine rock mass classification ratings and for the application of machine learning to address rock engineering problems.

scholarly journals Advances inRosettastructure prediction for difficult molecular-replacement problems

2013 ◽  
Vol 69 (11) ◽  
pp. 2202-2208 ◽  
Author(s):  
Frank DiMaio
Keyword(s):  
Structure Prediction ◽  
Prediction Methods ◽  
Molecular Replacement ◽  
Improved Method ◽  
Model Quality ◽  
Future Directions ◽  
Protein Structure Modeling ◽  
Improve Model ◽  
Difficult Cases

Recent work has shown the effectiveness of structure-prediction methods in solving difficult molecular-replacement problems. TheRosettaprotein structure modeling suite can aid in the solution of difficult molecular-replacement problems using templates from 15 to 25% sequence identity;Rosettarefinement guided by noisy density has consistently led to solved structures where other methods fail. In this paper, an overview of the use ofRosettafor these difficult molecular-replacement problems is provided and new modeling developments that further improve model quality are described. Several variations to the method are introduced that significantly reduce the time needed to generate a model and the sampling required to improve the starting template. The improvements are benchmarked on a set of nine difficult cases and it is shown that this improved method obtains consistently better models in less running time. Finally, strategies for best usingRosettato solve difficult molecular-replacement problems are presented and future directions for the role of structure-prediction methods in crystallography are discussed.

Analysis of Micro Vapor Bubble Growing Process in Open Capillary Microgrooves

2009 ◽  
Author(s):  
Chaohong Guo ◽  
Xuegong Hu ◽  
Liyuan Wu ◽  
Dawei Tang ◽  
Tao Wang
Keyword(s):  
Vapor Bubble ◽  
Growth Period ◽  
Improved Method ◽  
Equivalent Radius ◽  
Transfer Equations ◽  
Volume Increment ◽  
Micro Bubble ◽  
Calculation Results ◽  
Three Stages ◽  
Comparison Of The Results

Growing process of an individual micro bubble in open rectangular capillary microgrooves was theoretically analyzed in this study. Several common correlations of bubble growing radius for pool boiling, such as correlations of Zuber et al [1], Cooper et al [2], Labuntsov et al [3], and Zhao et al [4], were proved not precise. An improved method based on the dynamic microlayer model was presented in the paper. The method divided growing process of a micro vapor bubble into three stages: initial growing stage, normal and axial confined ellipsoidal growing stage, and axial subcylindrical growing stage. Heat transfer equations were established based on each stage’s characteristics. Growth period and volume increment of the micro vapor bubble were calculated in each stage. The calculation results show that growth of the micro vapor bubble is distinctly confined by geometric structure of microgrooves. The comparison of the results between calculation and experiment shows that the calculated bubble equivalent radius is consistent with the experimental results.

scholarly journals Three-Dimensional Numerical Modeling and Roof Deformation Analysis of Yuanjue Cave Based on Point Cloud Data

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhigang Meng ◽  
Manchao He ◽  
Zhigang Tao ◽  
Bin Li ◽  
Gang Zhao ◽  
...  
Keyword(s):  
Rock Mass ◽  
Numerical Calculation ◽  
Point Cloud ◽  
Three Dimensional ◽  
Calculation Model ◽  
Deformation Analysis ◽  
Cloud Data ◽  
Heritage Site ◽  
Calculation Results ◽  
Multifactor Coupling

Yuanjue Cave is the core exquisite cultural relic of the Dazu Stone Carvings World Cultural Heritage Site. For hundreds of years, with the continuous effect of natural forces and the erosion of various deterioration factors, the sidewall and roof rock mass of Yuanjue Cave were eroded, some parts of supporting rock mass were fragmented, and the boundary conditions of the rock mass have deteriorated, which have seriously endangered the Yuanjue Cave; once the roof collapses, the national treasure in the cave will be destroyed. In order to preevaluate the stability characteristics of the Yuanjue Cave rock mass and provide key parameters for the preventive protection of the Yuanjue Cave, this paper firstly established a refined database of key parameters of Yuanjue Cave and adjacent areas (geometry, geology, physical properties) based on three-dimensional laser point cloud scanning, a fine survey of adjacent areas, engineering geophysical prospecting, and indoor multifactor coupling tests. Then, based on FLAC3D finite difference numerical simulation technology, an accurate three-dimensional numerical calculation model of Yuanjue Cave was constructed. Finally, the model was used to analyze the roof stability of Yuanjue Cavern, revealing the deformation laws of the Yuanjue Cave roof under static load conditions, and the numerical calculation results were compared with the on-site measured results, verifying the feasibility of the high-precision modeling method, and the reliability of the numerical calculation results provided a reference for the preventive protection of the cultural relics of the cave temple.

scholarly journals Analisis Persedian Bahan Baku, Reorder Point dan Safety Stock Bahan Baku ADC-12

2020 ◽  
Vol 20 (2) ◽  
pp. 675
Author(s):  
Hazimah Hazimah ◽  
Yongki Antoni Sukanto ◽  
Nurlinda Ayu Triwuri
Keyword(s):  
Raw Materials ◽  
Raw Material ◽  
Economic Order Quantity ◽  
Order Quantity ◽  
Safety Stock ◽  
Reorder Point ◽  
Calculation Results ◽  
Descriptive Approach ◽  
Quantitative Descriptive ◽  
Optimal Calculation

The production process is very dependent on the availability of raw materials. An optimal calculation of raw material inventory is needed so that the company avoids the problem of lack or over stock of raw materials. This research aims to find out the quantity of raw material inventory, safety stock, and reorder point for ADC-12 raw materials.. This research uses a quantitative descriptive approach. Data sources obtained directly from the company. Analysis of the data used using the Economic Order Quantity method. Based on research and calculation results that have been done, if the company uses the EOQ method the quantity of raw material inventory is 80,861 kg. The quantity of the safety stock is 2,768 kg with a reorder point (ROP) of 14,038 kg.

Numerical Simulation Method Utilization in Water Gushing Yield Forecasting of Paoziling Tunnel in Hunan Province, China

2014 ◽  
Vol 580-583 ◽  
pp. 1392-1397 ◽  
Author(s):  
Yan Na Yang ◽  
Qiang Zhang ◽  
Mo Xu
Keyword(s):  
Rock Mass ◽  
Water Source ◽  
Simulation Method ◽  
Hunan Province ◽  
Analytic Method ◽  
Tunnel Engineering ◽  
Underground Engineering ◽  
Field Development ◽  
Hydrodynamic Field

Empirical analytic method and theoretical analytic method are usually applied to calculate and predict water gushing yield in the tunnel engineering in the past but have much limitations and errors. Ample water source, hydrodynamic conditions and expedite channels are essential for water-bursting accidents in railroad tunnel engineering. From a lot of study of fractal geometry in rock mass, it is found that the multi-dimension value of fissure network is colligate reflection of the length, the direction, space and the number of fissures, so the value can be used to describe the complicated frameworks in rock mass. But it is a sound tackle to quantities the complicated frameworks. Numerical simulating method is convinced to be applied to calculate and predict water gushing yield of tunnel and underground engineering. It focuses on analyzing texture characteristics of water-containing medium, building hydro-geological conceptual model, and modeling long-term hydrodynamic field development. An experimental application in Paoziling tunnel under-crossing mountain reservoirs in Hunan province was presented in this article, and long-term hydrodynamic field development had been obtained under the condition of drainage from the tunnel, and the gush yield in the tunnel during the process of storing water in the reservoir was also predicted.

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