scholarly journals Continuous Support for Roadways

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5801
Author(s):  
Krzysztof Mazurek ◽  
Marek Szyguła ◽  
Andrzej Figiel ◽  
Krzysztof Filipowicz
Keyword(s):  
Rock Mass ◽  
Mining Industry ◽  
Qualitative Behavior ◽  
Numerical Tests ◽  
Geological Conditions ◽  
New Type ◽  
Continuous Support ◽  
Characteristic Features ◽  
Yielding Support ◽  
Mine Roadways

Opening deeper coal seams requires constructing underground mine roadways in difficult geological conditions. Supporting of such roadways is subjected to a very high load from the rock mass. The types of roof supports used so far do not provide immediate support for the rock mass, which tends to converge the roadway, allowing for a rapid build-up of stresses in the surrounding rock mass. The article presents a new type of frame roadway support. This is a yielding support (consecutive arches are connected in a helical pattern), enabling the successive arches to be provided with initial load-bearing capacity already at the construction stage. The so-called unscrewing of the helix enables the arches to be pressed against the surface of the developed roadway with a controlled force. The introduction discusses the types of yielding roof supports used in the Polish mining industry and indicates their characteristic features. Further along in the article, the assumptions adopted for the construction of models to be tested and assumptions for the static and dynamic load to the models are defined, and the results of the model numerical tests are presented. The tests were aimed at comparing the qualitative behavior of the new roof support and the closed, circular support which is closest to it. The results of numerical tests confirmed the strength of the new solution not lower than the closed (circular) frame support, previously used in the most difficult geological conditions.

scholarly journals The Effect of Selected Factors on Floor Upheaval in Roadways—In Situ Testing

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5686
Author(s):  
Piotr Małkowski ◽  
Łukasz Ostrowski ◽  
Łukasz Bednarek
Keyword(s):  
Compressive Strength ◽  
Rock Mass ◽  
Measurement Data ◽  
Complex Form ◽  
Study Results ◽  
Geological Conditions ◽  
The Stability ◽  
Rock Mass Condition ◽  
Mine Roadways

The phenomenon of the floor upheaval occurs in virtually every type of rock mass and at every depth, accompanying the process of excavation of tunnels and headings. Despite its inconvenience, it is rarely studied because of the complexity of the process and the multiplicity of the factors causing deformations in floor rocks. To quantify the effect of the selected factors on floor upheaval, this article presents an analysis of results of in situ measurements carried out in three coal mine roadways at 15 measuring stations. These measurements were taken over varying periods of time, between 129 and 758 days. Groundwater and fault zones intersecting the excavations were considered as the key factors that affect floor upheavals. Therefore, the measurement bases were located at local faults and sites of water inflow. To compare the results, the stations were also located where the rock mass was not exposed to any factors other than stresses resulting from the depth of the excavation. The excavations were driven in various rocks and were located at different depths from 750 to 1010 m. The analyses of the study results show that the floor upheaval always depends on time and can be described in polynomial form: ufl = a·t2 + b·t + c or by a power function: ufl = a·tb. However, the further regression analyses show that roadway’s floor upheaval can be expressed by a complex form using the key parameters determining the phenomena. In the absence of an impact of geological factors on the stability of the excavation, the floor upheaval depends on floor rocks compressive strength σc and Young’s modulus E: ln(ufl)=a·ln(tσc)−bE−c; in the case of rock mass condition affected by water depends on the rock compressive strength reduction after submerging rock in water σcs 6h: ufl=a·t0.5−bσcs 6hσc+c and in the case of fault depends on the fault’s throw f: ufl=a·t0.8+b·f1.2−c. Statistical analysis has shown that the matching of the models to the measurement data is high and amounts to r = 0.841–0.895. Hence, in general, the analysis shows that the floor upheaval in underground excavation in any geological conditions may grow indefinitely.

scholarly journals A Hooked-Collar for Bridge Piers Protection: Flow Fields and Scour

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1251 ◽  
Author(s):  
Su-Chin Chen ◽  
Samkele Tfwala ◽  
Tsung-Yuan Wu ◽  
Hsun-Chuan Chan ◽  
Hsien-Ter Chou
Keyword(s):  
Laboratory Experiments ◽  
Horseshoe Vortex ◽  
Flow Fields ◽  
Bridge Pier ◽  
The Other ◽  
Bridge Piers ◽  
Vortex Strength ◽  
Numerical Tests ◽  
Scour Hole ◽  
New Type

A new type of collar, the hooked-collar, was studied through experiments and numerical methods. Tests were conducted using a hooked collar of a width of 1.25b and a height of 0.25b, where b is the bridge-pier width. The hooked-collar efficiency was evaluated by testing different hooked-collar placements within the bridge-pier, which were compared to the bridge-pier without any collar. A double hooked-collar configuration, one placed at the bed level and the other buried 0.25b, was the most efficient at reducing the scour hole. In other cases, a hooked-collar positioned 0.25b above the bed slightly reduced the scour hole and had similar scour patterns when compared to the pier without the hooked-collar. The flow fields along the vertical symmetrical plane in the experiments are also presented. Laboratory experiments and numerical tests show that maximal downflow is highly reduced along with a corresponding decrease in horseshoe vortex strength for the experiments with the hooked-collar, compared to cases without the hooked-collar. The flow fields reveal that the maximum turbulent kinetic energy decreases with the installation of the hooked-collar.

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.

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.

scholarly journals Determination of the transfer step of the ore chute while mining the technogenic deposit of the bulk type

2020 ◽  
Vol 166 ◽  
pp. 02004
Author(s):  
Volodymyr Peregudov ◽  
Ihor Hryhoriev ◽  
Serhii Joukov ◽  
Yulian Hryhoriev
Keyword(s):  
Raw Materials ◽  
Mining Industry ◽  
Process Conditions ◽  
Geological Conditions ◽  
Scientific Task ◽  
Technogenic Deposit ◽  
Mining Works ◽  
The Cost

Further development of the open mining works on the domestic enterprises will be accompanied by the worsening of mining-geological conditions and declining of the quality of iron ore raw materials. In the same time, the accumulated mining wastes, that can make the technogenic deposits, pass into one of the important sources of the mineral raw materials. Taking into account this thing, the development and implementation of the modern technological circuits of the technogenic deposit development is an actual calling for mining industry, and determination and optimization of process conditions of the technogenic deposit development – is the scientific task of this publication. The obtained results of studies of the optimum step value of the ore chute transfer during the technogenic deposit development can be used by design organizations and mining enterprises for designing works. The obtained methodology and the proposed mathematical dependencies will reduce the cost of mining of the technogenic deposit due to the reasonable timely transfer of the open ore chute.

scholarly journals Key Factors Affecting the Deformation and Failure of Surrounding Rock Masses in Large-Scale Underground Powerhouses

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Meng Wang ◽  
Jia-wen Zhou ◽  
An-chi Shi ◽  
Jin-qi Han ◽  
Hai-bo Li
Keyword(s):  
Rock Mass ◽  
Large Scale ◽  
Surrounding Rock ◽  
Rock Masses ◽  
Affecting Factors ◽  
Key Factors ◽  
Underground Powerhouse ◽  
Deformation And Failure ◽  
Factors Affecting ◽  
Geological Conditions

The stability of the surrounding rock masses of underground powerhouses is always emphasized during the construction period. With the general trends toward large-scale, complex geological conditions and the rapid construction progress of underground powerhouses, deformation and failure issues of the surrounding rock mass can emerge, putting the safety of construction and operation in jeopardy and causing enormous economic loss. To solve these problems, an understanding of the origins and key affecting factors is required. Based on domestic large-scale underground powerhouse cases in the past two decades, key factors affecting the deformation and failure of the surrounding rock mass are summarized in this paper. Among these factors, the two most fundamental factors are the rock mass properties and in situ stress, which impart tremendous impacts on surrounding rock mass stability in a number of cases. Excavation is a prerequisite of surrounding rock mass failure and support that is classified as part of the construction process and plays a pivotal role in preventing and arresting deformation and failure. Additionally, the layout and structure of the powerhouse are consequential. The interrelation and interaction of these factors are discussed at the end of this paper. The results can hopefully advance the understanding of the deformation and failure of surrounding rock masses and provide a reference for design and construction with respect to hydroelectric underground powerhouses.

Study on Structural Design and Driving Process of a Subway Station with Large Transection by Tunneling Method

2013 ◽  
Vol 353-356 ◽  
pp. 1325-1328 ◽  
Author(s):  
Xiao Jun Zhou ◽  
Chang Yu Yang
Keyword(s):  
Rock Mass ◽  
Structural Design ◽  
Subway Station ◽  
Great Success ◽  
Construction Process ◽  
Tunneling Method ◽  
Geological Conditions ◽  
Cut Method ◽  
Transfer Station ◽  
Composite Lining

Structural design and construction process for a subway station consists of two tunnels with large transection are discussed according to its function and geological conditions of rock mass in this paper. A composite lining is designed to support surrounding rock, and partial bench cut method, side drift method are utilized to build the special subway transfer station in rock mass. The practice of the designed scenario proves to be a great success and attains the safe construction of the station by tunneling method.

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.

Stability of development drifts in difficult geological conditions of Starobin deposit

2020 ◽  
pp. 26-32
Author(s):  
B. I. Petrovsky ◽  
◽  
V. A. Misnikov ◽  
K. A. Erokhin ◽  
A. B. Petrovsky ◽  
...  
Keyword(s):  
Potassium Salt ◽  
Deep Level ◽  
Maximum Efficiency ◽  
Salt Deposit ◽  
Support Design ◽  
Underground Openings ◽  
Geological Conditions ◽  
Stability Of Development ◽  
Yielding Support ◽  
Roof Rocks

Extraction of the remaining reserves at the Starobinsk potassium salt deposit is associated with degradation of geological conditions as the content of clay beds in roof rocks increases with depth. The article presents the underground test data on the most promising techniques of roof support in development entries in deep-level unstable rocks in the Starobinsk potassium salt deposit. In an operating mine, various combinations of different support types and ground control approaches were tested, namely, compensation voids (slotting, racking) and long roof bolting. It is found that the maximum efficiency of development heading support is achieved with the combination of destressing headings and compensation slots. These flow charts are applicable to a depth of 860–900 m at the clay bed content of 35%. At the depths greater than 900 m and at the clay bed content higher than 35%, each underground excavation should have a specific support type. In extremely complex conditions at any depth and at the clay bed content from 35 to 60% in the roof, the support design for long underground openings with a span to 3.8 m, without slots in the sidewalls can involve roof scaling up to the roof arch (pressure arch) and installation of special-shape and expansion-type yielding support in sidewalls.

Sign in / Sign up

Export Citation Format

Share Document