scholarly journals A Vibration-Isolating Blast Technique with Shock-Reflection Device for Dam Foundation Excavation in Complicated Geological Conditions

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Haoran Hu ◽  
Wenbo Lu ◽  
Peng Yan ◽  
Ming Chen ◽  
Qidong Gao
Keyword(s):  
Rock Mass ◽  
Field Experiments ◽  
Vertical Direction ◽  
Wave Impedance ◽  
Shock Reflection ◽  
Dam Foundation ◽  
Geological Conditions ◽  
Production Experiment ◽  
Bench Blasting ◽  
Foundation Rock

Under complicated geological conditions, the vibration in the dam foundation caused by blasting can lead to further deterioration of the foundation rock mass and adversely affect the safety of foundation. In order to effectively control the vibration in dam foundation rock mass, a new bench blasting technique with shock-reflection device is proposed. It introduces a shock-reflection device consisting of high wave impedance block and cushion material, which is placed at the bottom of vertical borehole. This shock-reflection device can effectively reflect the explosion shock wave from vertical direction to horizontal direction after detonation, which can make blasting energy concentrated on the rock mass above dam foundation, so the vibration in the foundation can be controlled. Field blasting experiment was carried out to contrast the blasting induced vibration in foundation rock by bench blasting with shock-reflection device and conventional bench blasting. The results indicate that the vibration in the foundation rock can be reduced by 30%~57%. In addition, the vibration at the bottom of the borehole is also demonstrated by numerical simulation, with results similar to the field experiments. The production experiment results show that the new blasting technique can replace the conventional excavation method of dam foundation in complicated geological conditions, and the new blasting technique has been successfully applied to the Baihetan dam foundation excavation.

The Arch Dam Foundation Rock Mass Unloading and Relaxation Deformation Characteristics and their Monitoring Result Analysis

2011 ◽  
Vol 255-260 ◽  
pp. 3514-3523
Author(s):  
Shi Sheng Li ◽  
Ze Rong Dong ◽  
Qi Li ◽  
Hua Zhao ◽  
Hui Zhang
Keyword(s):  
Rock Mass ◽  
Scientific Basis ◽  
Arch Dam ◽  
Design Parameters ◽  
Dam Foundation ◽  
Whole Process ◽  
Deformation Test ◽  
Dam Stability ◽  
Result Analysis ◽  
Foundation Rock

After foundation excavation for a dam of a hydropower project, the rock mass would be unloaded and relaxed and its mechanical parameters would be lowered, thus influencing the dam stability. This paper makes an analysis of the deformation development law of the unloading rock mass of the dam foundation by analyzing the advance deformation of the dam foundation before excavation and the unloading rebound deformation of the dam foundation after excavation, and by analyzing the monitoring results of the compressive deformation after concreting of the dam and of the whole process deformation after impounding of the reservoir taking into account the results of both deformation test and acoustic test, which provides scientific basis for quality assessment of the arch dam foundation rock mass and for readjustment of the dam foundation rock mass mechanics design parameters, thus giving a reference to projects of the kind.

Numerical Research on the Gravity Dam Deep Anti-Sliding with Engineering Mechanics Based on Damage Theory

2014 ◽  
Vol 910 ◽  
pp. 289-296
Author(s):  
Shuang Liu ◽  
Qing Wen Ren ◽  
Chen Lu Zhou
Keyword(s):  
Rock Mass ◽  
Numerical Model ◽  
Damage Mechanics ◽  
Failure Process ◽  
Gravity Dam ◽  
Instability Criterion ◽  
Gravity Dams ◽  
Dam Foundation ◽  
Sliding Stability ◽  
Foundation Rock

Currently, researches on the gravity dam deep and shallow anti-sliding stability mainly focus on the analysis method and instability criterion, while the studies on specifically test the breakage of gravity dams due to weakening foundation rock mass and structural planes under loading are rare. Based on damage mechanics theory, this paper established a numerical model that analyzed the damage failure process of dam foundation rock mass. Taking two typical gravity dam models as the study objects, the damage processes of the dam foundations were simulated dynamically. Additionally, a comparison with other two traditional methods further validated the correctness and feasibility of the numerical model. In sum, the study findings point out that the numerical model is not only applicable to the study of the breakage mechanism of dam foundation rock mass, but also can be used as a new method to analyze problems related to deep anti-sliding stability of gravity dams.

Numerical Analysis of Damage to Retained Rock Mass of Dam Foundation Caused by Blasting Excavation

2011 ◽  
Vol 255-260 ◽  
pp. 4256-4261 ◽  
Author(s):  
Hong Yan Liu ◽  
Ming Wang
Keyword(s):  
Rock Mass ◽  
Wave Attenuation ◽  
Damage Model ◽  
Crack Density ◽  
Material Model ◽  
Rock Blasting ◽  
Dam Foundation ◽  
Model Library ◽  
Geological Conditions ◽  
Blasting Excavation

On basis of the existed TCK model, the establishment process of a new rock blasting damage model is discussed by considering the relationship of crack density Cd, which indicates the shock damage extent of rock, and sound wave attenuation coefficient ap. Then, this model is inserted into the user-defined material model library of ANSYS/LS-DYNA3D software to construct the new damage model. Numerical simulation of damage to retained rock mass of dam foundation caused by rock blasting excavation in dam region with this model. Calculation results show that: as far as the blasting parameters and geological conditions in this paper, the damage to retained rock mass below caused by rock blasting excavation above is basically limited to the scope of 1.5m below the bottom of blasthole, and damage degree gradually reduces from the bottom of blasthole to faraway. Meanwhile, blasting will not cause rock mass to open along soft layer inside, whose maximum calculation displacement is only 3mm. The calculation result can be referred by the practical engineering.

scholarly journals Case Study: In Situ Experimental Investigation on Overburden Consolidation Grouting for Columnar Jointed Basalt Dam Foundation

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-18 ◽  
Author(s):  
Jinxi Dou ◽  
Mengxia Zhou ◽  
Zhilin Wang ◽  
Kexiang Wang ◽  
Shui Yuan ◽  
...  
Keyword(s):  
Rock Mass ◽  
Engineering Application ◽  
Deformation Modulus ◽  
Physical And Mechanical Properties ◽  
Jinsha River ◽  
Dam Foundation ◽  
Columnar Jointed Basalt ◽  
Average Improvement ◽  
Lugeon Test ◽  
Foundation Rock

The dam foundation rock mass, at the Baihetan hydropower station on the Jinsha River, is mainly columnar jointed basalt, with faults and fissures developed. Considering adverse factors such as the unloading relaxation or the opening of the fissures due to excavation blasting, consolidation grouting is needed to improve the integrity of the dam foundation rock mass. According to the physical and mechanical properties of columnar jointed basalt and the continuity of construction, the effectiveness of overburden consolidation grouting is experimentally studied. The results show that this grouting technology can obviously improve the integrity and uniformity of a dam foundation rock mass and reduce the permeability of the rock mass. After grouting, the average increase in the wave velocity of the rock mass is 7.3%. The average improvement in the deformation modulus after grouting is 13.5%. After grouting, the permeability of 99% of the inspection holes in the Lugeon test section had Lugeon values of no more than 3 LU. This improvement is considerable and provides a case to engineering application.

Cryogels as a solution to the issues of environmental management and trunk pipeline operation in Arctic

2020 ◽  
Vol 10 (2) ◽  
pp. 173-185
Author(s):  
Lyubov K. Altunina ◽  
◽  
Vladimir P. Burkov ◽  
Petr V. Burkov ◽  
Vitaly Y. Dudnikov ◽  
...  
Keyword(s):  
Composite Materials ◽  
Field Experiments ◽  
Oil And Gas ◽  
Soil Layer ◽  
Soil Microflora ◽  
Russian Arctic ◽  
Thaw Cycle ◽  
Trunk Pipeline ◽  
Geological Conditions ◽  
Spatial Lattice

In the Russian Arctic, a soil cryostructuring technique (i.e. strengthening of soil horizons with cryogel-based composite materials with no excavation of unstable soils required) seems to be showing promise. Experiments have proven that mechanical and thermal insulation properties attributed to cryogels make them appropriate for use in strengthening and thermally insulating the soil, while their structure makes it possible to form a stable vegetation cover. Field experiments have confirmed that cryostructuring efficiently strengthens the soil layer with cryogels stimulating soil microflora. An experience of using cryotropic compositions in the oil and gas sector was described. Notably, cryogels can be used to strengthen unstable soil foundations of trunk pipelines, as well as to bind soil (e.g. on slopes). In addition, cryogels are advised for use in engineering protection to prevent the uneven settlement of a trench base and its creep: thus, cryogels are pumped into the soil of the trench bottom base to create a support system representing a spatial lattice. After the first freeze and thaw cycle, cryotropic material is formed and then increases its strength and elasticity with each new cycle. More broadly, opportunities have been considered regarding cryogels used in various engineering and geological conditions, while taking into account the outcomes of landscape and territorial analysis. It was concluded that cryogel-based composite materials are a promising innovative scientific field expanding technological capabilities for developing and using spaces and resources in the Russian Arctic.

scholarly journals Substantiation of Safe Conditions During Undermining of Hydraulic Waste Disposal

2018 ◽  
Vol 41 ◽  
pp. 01007
Author(s):  
Yuriy Kutepov ◽  
Aleksandr Mironov ◽  
Maksim Sablin ◽  
Elena Borger
Keyword(s):  
Rock Mass ◽  
Waste Disposal ◽  
Coal Mine ◽  
Water Body ◽  
Water Inflow ◽  
Open Pit ◽  
Coal Seams ◽  
Geological Conditions ◽  
Mine Workings ◽  
Mine Dump

This article considers mining and geological conditions of the site “Blagodatny” of the mine named after A.D. Ruban located underneaththe old open pit coal mine and the hydraulic-mine dump. The potentially dangerous zones in the undermined rock mass have been identified based onthe conditions of formation of water inflow into mine workings. Safe depthof coal seams mining has been calculated depending on the type of water body – the hydraulic-mine dump.

scholarly journals Analysis of rock mass dynamic impact influence on the operation of a powered roof support control system

2018 ◽  
Vol 29 ◽  
pp. 00006 ◽  
Author(s):  
Dawid Szurgacz ◽  
Jaroław Brodny
Keyword(s):  
Rock Mass ◽  
Real Life ◽  
High Energy ◽  
Hard Coal ◽  
Underground Excavation ◽  
Dynamic Impact ◽  
Support Unit ◽  
Geological Conditions ◽  
Innovative Solutions ◽  
Roof Support

A powered roof support is a machine responsible for protection of an underground excavation against deformation generated by rock mass. In the case of dynamic impact of rock mass, the proper level of protection is hard to achieve. Therefore, the units of the roof support and its components are subject to detailed tests aimed at acquiring greater reliability, efficiency and efficacy. In the course of such test, however, it is not always possible to foresee values of load that may occur in actual conditions. The article presents a case of a dynamic load impacting the powered roof support during a high-energy tremor in an underground hard coal mine. The authors discuss the method for selecting powered roof support units proper for specific forecasted load conditions. The method takes into account the construction of the support and mining and geological conditions of an excavation. Moreover, the paper includes tests carried out on hydraulic legs and yield valves which were responsible for additional yielding of the support. Real loads impacting the support unit during tremors are analysed. The results indicated that the real registered values of the load were significantly greater than the forecasted values. The analysis results of roof support operation during dynamic impact generated by the rock mass (real life conditions) prompted the authors to develop a set of recommendations for manufacturers and users of powered roof supports. These include, inter alia, the need for innovative solutions for testing hydraulic section systems.

3-D fracture network dynamic simulation based on error analysis in rock mass of dam foundation

2018 ◽  
Vol 25 (4) ◽  
pp. 919-935 ◽  
Author(s):  
Deng-hua Zhong ◽  
Han Wu ◽  
Bin-ping Wu ◽  
Yi-chi Zhang ◽  
Pan Yue
Keyword(s):  
Rock Mass ◽  
Error Analysis ◽  
Dynamic Simulation ◽  
Fracture Network ◽  
Network Dynamic ◽  
Dam Foundation ◽  
Simulation Based

scholarly journals Deformation Characteristics and Control Method of Kilometer-Depth Roadways in a Nickel Mine: A Case Study

2020 ◽  
Vol 10 (11) ◽  
pp. 3937
Author(s):  
Guang Li ◽  
Fengshan Ma ◽  
Jie Guo ◽  
Haijun Zhao
Keyword(s):  
Rock Mass ◽  
Failure Modes ◽  
Control Method ◽  
Steel Tube ◽  
In Situ Monitoring ◽  
Zonal Disintegration ◽  
Deformation Characteristics ◽  
Geological Conditions ◽  
Ground Stress

Deformation failure and support methods of roadways have always been critical issues in mining production and safety, especially for roadways buried in complex engineering geological conditions. To resolve these support issues of kilometer-depth roadways under high ground stress and broken rock mass, a case study on the roadways in the No. 2 mining area of Jinchuan Mine, China, is presented in this paper. Based on a detailed field survey, the deformation characteristics of the roadways and failure modes of supporting structures were investigated. It was found that the horizontal deformations were serious, and the primary support was not able to control the surrounding rock well. Additionally, a broken rock zone test was carried out, which indicated that a zonal disintegration phenomenon occurred around the roadways and the maximum depth of the fractured zone was more than 4.8 m. In order to effectively limit the deformation in the roadways, a new support scheme called the “multistage anchorage + concrete-filled steel tube” was put forward. To further assess the support behavior of the new method, we selected a test roadway in the research area, and numerical simulations and in-situ monitoring were conducted. The findings suggest that the roadway’s serious deformation under high ground stress and broken rock mass could be successfully controlled by the new control method, which can provide a reference for other engineering solutions under similar geological conditions.

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