Main Roadway Research Articles

Position optimisation for a roadway under small coal mines in same coal seam: a case study

AbstractAccording to the failure law of the 1070 main roadway, this paper proposes a reasonable position for large section roadways under small coal mines and a design for seven roadway positions. RS2 software was used to establish a numerical model to select a reasonable position for the roadway. The influences of roadway positions on roof separation amount, roof subsidence, lateral displacement on the ribs, vertical stress on ribs and roadway failure areas were revealed. On the basis of influence laws, reasonable positions for the roadway could be determined. In this study, a center distance of 5 m was deemed a reasonable position. Finally, an industrial test was conducted at the original roadway. The experimental results indicate that the deformation of the roadway could be well controlled and the roadway position is reasonable.

Study on Support Optimization of mining roadway in deep steeply dipping coal seam

In order to solve the problem of the failure phenomenon of roof fall and the inward extrusion of two roadsides in main roadway of 31205 working face of Zhubai coal mine, the theoretical analysis, field measurement and numerical simulation were adopted to study the rock breakage and instability of roadway’s and put forward the differential anchor cable and bolt targeted support solution. Industrial tests and the roadway pressure observation were carried out in 31205 main roadway. The field application results showed that the deformation and break of roadway surrounding rock is effectively controlled, the supporting cost was reduced and the supporting effect was remarkable.

Evaluating determinants of shale gas well locations in an urban setting

This research aims to identify factors that contribute to gas well operator pad site location decisions in Denton, Texas. Using new production technologies, a wave of shale gas extraction between 2000 and 2014 resulted in the development of 854 gas wells on 539 pad sites within 2000 US Census block groups that include parts of the City of Denton. For pad site placement, we consider multiple location decision factors. We use both Poisson and zero-inflated Poisson regressions for the analyses. Unsurprisingly, census block groups sitting atop the Barnett Shale have more pad sites than block groups away from the Barnett Shale. Beyond that, we find statistically significant negative correlations between both housing unit density and the percentage of block group land area falling within the Denton city limits indicating that both urban development, and the regulations that go along with it, affect pad site development. However, we do not find that setback regulations in less urbanized areas curtail pad site development. We also find that access to pipeline infrastructure—needed to transport gas from each pad site—has a positive effect on pad site development. This indicates that production costs associated with potential sites do matter. It is unusual for extraction operators to share pipelines connecting pad sites to transmission lines. This could have the effect of limiting competition for natural gas property rights and reduce royalties paid to mineral rights owners. In terms of demographic or socioeconomic factors that may matter, we find income is negatively correlated with pad site development while education is positively correlated with pad site development. Finally, we find evidence that pad sites cluster. Clustering could advantage access to main roadways, reduce costs to extend pipelines, or be an outcome of urban developments that constrain pads from locating in certain areas.

Multiple-criteria analysis model to the location of dry ports in urban areas: a case study in Garuva City, Santa Catarina State

Abstract This article studied the location of dry ports from the perspective of reducing impacts caused by seaport activities on the urban environment. The main objective was to construct a model based on multiple-criteria decision analysis coupled with the geographical information system for selecting areas subject to the location of dry ports. An important point was the definition of restriction and factor criteria for the preparation of this model. The distance from the seaport was defined as the most relevant criterion, followed by the road hierarchy network, population density, vegetation, and declivity, respectively. The predominant restrictive criteria were: permanent conservation areas and non-building zones. For the validation of the model presented, it was necessary to perform a case study on a city located near a seaport, and that has been legalized seaport activities in its legislation. The result showed that the areas nearest to the port, with less density of household units, and located near main roadways are the most feasible for location of dry ports. It was proven that the usage of multi-criteria analysis for selecting areas subject to the location of dry ports can be a manner for added support in the preparation of master plans for cities surrounded by seaport areas.

Study on Anchorage Failure and Bolting Measures of Roadway in Weak Rock

A mechanical model for anchorage and surrounding rock was established against the failure of bolting system, the differential equation of load-transfer was solved and the shape and depth of excavation damaged zone (EDZ) of the surrounding rock was analysed. The results show that to achieve full performance of rockbolts materials and to lengthen its service life, two requirements must be met. One is that the load of rockbolt is no more than its load-bearing capacity. The other one is that the anchorage should be located in stable elastic zone. The shape of EDZ is determined by the magnitude and direction of in-situ stress. Reasonable bolting design should abandon the traditional design of uniform support strength. Rather, should adopt coordinated support and nonuniform support design according to the shape of EDZ in field. Based on the above principles, a new type of combination rockbolt with the effect of high resistance and yield pattern was adopted for the new bolting scheme in the main roadway of Puhe Coal Mine. By analyzing the data collected in field, it is concluded that the combination rockbolt can solve the problem that appearing pull-out failure of rockbolts and tensile failure of cablebolts.

Mechanical analysis of a vertical-wall, semicircular-arch roadway and a repair technique using double-shell support

Roadways in coal mines normally have two vertical side walls and a semicircular arch-shaped roof when viewed in cross section, a design conducive to the stability of surrounding rocks. The North 1 main roadway in Duerping Coal Mine has suffered severe damage and the conventional support method employed there is incapable of ensuring long-term stability of the surrounding rocks. This study provides a mechanical analysis of this vertical-wall, semicircular-arch (VWSA) roadway using a mechanical model. Formulas describing stresses in the rocks surrounding a VWSA roadway were derived through complex analysis. The stress distribution in the surrounding rocks was then predicted using the formulas. Based on the results, a double-shell support structure consisting of an internal shell, a flexible interlayer, and an external shell was developed as a new technique to stabilize surrounding rocks. The functional mechanisms of the three parts and the specific construction procedure are detailed in this paper. Moreover, the key technical parameters were optimized through a comparative analysis of the surrounding rock’s deformation behavior for different shell and interlayer thicknesses. After implementation of this technique, the floor heave, relative displacement between two sides, and roof lowering in the North 1 main roadway decreased to 82, 185, and 161 mm, respectively, which meet the requirements for long-term service. This verifies the effectiveness of the proposed technique in surrounding rock control.

Effect of bypasses on vehicular traffic through a series of signals

We study the dynamic motion of a vehicle moving through the series of traffic signals on a roadway with bypasses. A vehicle moves on either main roadway or bypass. There are all signals on the main roadway and signals are controlled by both cycle time and phase difference. The dynamic model of the vehicular motion is described in terms of the nonlinear map. The vehicular motion is studied on the roadway with bypasses and without bypasses. The vehicular motion changes highly by the signal control on the roadway with bypasses. It is found that the travel time decreases highly by the use of bypasses for specific values of cycle time but does not change for other values of cycle time. Also, the dependence of the travel time on the cycle time is derived at the green-wave strategy.

Experimental Research on the Impactive Dynamic Effect of Gas-Pulverized Coal of Coal and Gas Outburst

Coal and gas outburst is one of the major serious natural disasters during underground coal, and the shock air flow produced by outburst has a huge threat on the mine safety. In order to study the two-phase flow of a mixture of pulverized coal and gas of a mixture of pulverized coal and gas migration properties and its shock effect during the process of coal and gas outburst, the coal samples of the outburst coal seam in Yuyang Coal Mine, Chongqing, China were selected as the experimental subjects. By using the self-developed coal and gas outburst simulation test device, we simulated the law of two-phase flow of a mixture of pulverized coal and gas in the roadway network where outburst happened. The results showed that the air in the roadway around the outburst port is disturbed by the shock wave, where the pressure and temperature are abruptly changed. For the initial gas pressure of 0.35 MPa, the air pressure in different locations of the roadway fluctuated and eventually remain stable, and the overpressure of the outburst shock wave was about 20~35 kPa. The overpressure in the main roadway and the distance from the outburst port showed a decreasing trend. The highest value of temperature in the roadway increased by 0.25 °C and the highest value of gas concentration reached 38.12% during the experiment. With the action of shock air flow, the pulverized coal transportation in the roadway could be roughly divided into three stages, which are the accelerated movement stage, decelerated movement stage and the particle settling stage respectively. Total of 180.7 kg pulverized coal of outburst in this experiment were erupted, and most of them were accumulated in the main roadway. Through the analysis of the law of outburst shock wave propagation, a shock wave propagation model considering gas desorption efficiency was established. The relationships of shock wave overpressure and outburst intensity, gas desorption rate, initial gas pressure, cross section and distance of the roadway were obtained, which can provide a reference for the protection of coal and gas outburst and control of catastrophic ventilation.

원주시 시가지 주요도로의 조명특성 및 개선방안연구

원주시 시가지 주요도로의 조명특성 및 개선방안연구

School zone safety diagnosis using automated conflicts analysis technique

School safety is a high priority for road safety agencies worldwide due to the growing concerns about student safety and emphasis on community livability. However, the lack of consistent data available at schools makes it challenging for engineers to understand the safety issues faced accurately. Traffic conflicts have been advocated in the literature as a surrogate safety measure due to the advantages it offers for road safety evaluations. This paper demonstrates the capability of automated traffic safety diagnosis at a school using computer vision techniques. The selected school is located in a residential area in the City of Edmonton, Alberta, and is on a main roadway in the neighbourhood. The age group of the school is from 5 to 16 years old (corresponding to Grade 1 to 9 respectively). Data are collected during the fall and winter terms. The severity and frequency of conflicts and traffic violations were analyzed to quantify the safety concerns. These concerns included driving violations, jaywalking violations as well as conflicts between pedestrians and vehicles as well as between vehicles and each other. Hourly and seasonal trends were observed and analyzed to assist in the selection of treatments and recommendations to improve the safety around schools. The results show that pedestrian safety has improved in winter due to lower vehicle speeds.

Mercury emissions from dynamic monitoring holes of underground coal fires in the Wuda Coalfield, Inner Mongolia, China

The Wuda Coalfield, Inner Mongolia, China, is one of the largest coalfields suffering from coal fires in China, and has experienced fires for >50years. With the aim of observing the active state of underground coal seam fires to protect the main roadways of the coal mine, 44 drill holes were drilled in five fire areas of the Suhaitu coal mine to monitor gas emissions. A LumexRA-915+ Portable Mercury Analyzer was used to measure mercury concentrations in the exhaust gas. The drill holes exhibited high gaseous mercury concentrations, with an average of 4165ng/m3 (34–62,513ng/m3, n=1584), which was 45 times higher than that measured in the near-surface atmosphere around the drill holes. This finding indicates that the mercury emissions originate from underground coal fires. Furthermore, mercury concentration has a positive correlation with CO content and gas temperature, implying that mercury has the potential to act as a supplementary coal-fire index gases to monitor the prevailing underground coal fire in north China on the basis of traditional indicators. Whether it can perform satisfactorily in practical applications requires further comprehensive study.

Numerical Study on Effect of Longwall Mining on Stability of Main Roadway under Weak Ground Conditions in Indonesia

Numerical Study on Effect of Longwall Mining on Stability of Main Roadway under Weak Ground Conditions in Indonesia

Traffic Control Method on Efficiency of Urban Expressway Accompanied Frequent Aggressive Driving Behavior

In order to ensure that traffic capacity is stable, and avoid incident congestion is anabatic, a double-layer ramp-metering model is proposed in this paper to control the traffic flow at each on-ramp, nearby incident congestion. The function of the lower model is to recognize where the incident congestion exists, based on an adaptive neural network, whose inputs are traffic flow, velocity and density. The outputs of the lower model are the section number where the congestion occurs and the ramp number which should be controlled. If there is congestion, the upper model would be activated. The function of the upper model is to calculate the control strategy. The required control ramp number from the lower model would be transmitted to the upper model together with the real-time state of controlled section. The upper model would calculate the ramp-metering ratio for each required ramp by minimizing the main time cost, total average queue length and equity index. In order to describe the traffic state more accurately, a tailored traffic model for urban freeway in China is established in the upper model to get the prediction, which considers the speed-limited value on main roadway, and corrects the calculation method of traffic flow state on origin point and exit ramp. The simulation results show the double model is effective to control the incident congestion induced by aggressive behavior.

Spatial distribution characteristics and optimized reconstruction analysis of China’s rural settlements during the process of rapid urbanization

The population density of rural areas is generally lower than before due to rapid industrialization. Spatial optimized reconstruction of rural settlements is the key to rural sustainable development. Analyzing the distribution characteristics of rural settlements and their impact has profound implications for rural reconstruction. Several types of spatial distribution of rural settlements, such as clustered, random, and uniform discrete distribution, were found in China with significant regional differences. Rural settlements were denser in the southeastern regions compared to the northwestern regions. In regions such as plains, the spatial distribution of rural settlements was denser and the spatial distribution modes were mainly random and disperse. In regions such as cold alpine areas and desert fringes, the rural settlements density was low and mainly clustered. In the transition zone between hills and mountains, the density of rural settlements was high and the spatial distribution mode was mainly random. Rural settlements distribution was influenced by traditions and the economy, with economic development becoming increasingly influential. Additional factors that affected rural settlements distribution included average distance to main roadway, agricultural machinery, per capita grain production, per capita arable land, population density, elevation, precipitation, etc. Multiple distribution patterns should be used to reconstruct rural spaces in different geographical areas. Typical patterns included radially balanced, central land distribution mode; radially imbalanced distribution mode; multicore central land distribution mode, and corridor balanced and imbalanced distribution modes.

Whole section anchor–grouting reinforcement technology and its application in underground roadways with loose and fractured surrounding rock

Strata control technology for roadways with loose and fractured surrounding rock is one of the most challenging areas in underground roadway support. Based on the case of the serious deformations that occurred in a western main roadway of a Chinese coal mine, this paper analyzes the characteristics and influencing factors of deformation of roadways with loose and fractured surrounding rock. A mechanical model of the roadway’s surrounding rock has been established to study the different forces at play in the plastic zone of the roadway via means of site observation, theoretical analysis, numerical simulation and onsite experiments. Based on the double shell anchor–grouting reinforcement mechanism, whole section anchor–grouting reinforcement technology (WSAGRT) was implemented in the coal mine with the pertinent support parameters optimized by numerical simulation. The results show that the deformation of the rock surrounding the roadway has been held in check effectively, and thus WSAGRT warrants a safer and more effective mining environment.

Determination of Abutment Pressure in Coal Mines with Extremely Thick Alluvium Stratum: A Typical Kind of Rockburst Mines in China

This paper investigates the abutment pressure distribution in coal mines with extremely thick alluvium stratum (ETAS), which is a typical kind of mines encountering frequent intense rockbursts in China. This occurs due to poor understanding to abutment pressure distribution pattern and the consequent inappropriate mine design. In this study, a theoretical computational model of abutment pressure for ETAS longwall panels is proposed based on the analysis of load transfer mechanisms of key stratum (KS) and ETAS. The model was applied to determine the abutment pressure distribution of LW2302S in Xinjulong Coal Mine; the results of stress and microseismic monitoring verified the rationality of this model. The calculated abutment pressure of LW2302S was also used in the terminal mining line design of LW2301N for rockburst prevention, successfully protecting the main roadway from the adverse influence of the abutment pressure.

Walk or Drive between Stores? Designing Neighbourhood Shopping Districts for Pedestrian Activity

What design features are associated with people choosing to walk vs. drive between activities within shopping districts? This exploratory study used mixed-logit discrete choice modelling to analyze survey responses from 286 retail pharmacy store customers who travelled by personal automobile to one of 20 San Francisco Bay Area shopping districts, and then visited at least two activity locations within the district. The 91 customers who walked rather than drove within the shopping district tended to travel shorter distances and have several other common personal characteristics. After controlling for these factors, respondents were significantly more likely to walk when the main commercial roadway had fewer driveway crossings and a lower speed limit.

Roadway Anchor Support Design Method Based on the “Three Zones” of Roadway Roof

Aiming at the problem of serious deformation and failure of the surrounding rock of the main roadways in diabase zone in west wing on-500m leve in Dongbaowei Coal Mine and roof caving occurring several times, the rupture characteristics of roadway roof rock was observed in this paper. And the observation result shows that the rupture of the roof rock of the roadways in diabase zone has obvious zoning characteristics, and the roadway roof rock is divided into three zones: fragmentation zone, fissure zone and intact rock zone. According to this, this paper introduced a new concept of controlling roadway roof subsidence and redesigned the support parameters of the roof of the roadway in diabase zone. The deformation monitoring of the testing roadway roof rock was carried out, and the monitoring result shows that the anchor supporting scheme which was based on the “three zones” of roadway roof could control the roof rock deformation better. This indicates that roadway anchor support design method which is based on the “three zones” of roadway roof is correct and feasible.

Research on Loose Circle Test of Deep Broken Roadway

To control the stability of deep well broken surrounding rock, single-hole sonic method is used to test the loose circle of-1180 east-rock main roadway and its damage range. The study indicates the loose circle is about 1.8 ~ 2.2 m, which is typical large loose circle. And its button is slightly larger than two sides’, right side slightly larger than left. The roadway rock has some engineering features of soft rock. The broken and expand deformation of loose circle does large, difficult to support. Combined support is usually used in this rock condition.

Investigating Land-Use Change on Street Tree Ecosystems

In the early 1940’s, during the early stages of the Manhattan Project (WWII), of rural communities in Anderson County, Tennessee was rapidly converted into laboratory facilities and the city of Oak Ridge. The environment that became Oak Ridge experienced not only pollutants from the laboratory activities, but also alterations from the land-use change from rural to urban areas. Therefore, a study was conducted to determine the impacts of land-use change from rural to urban area on 1) street tree diversity and performance; and 2) the biological, chemical and physical properties, and nutrient dynamics of street tree ecosystem soils. There were a total of 607 street trees, composed of 37 different species, on the five main roadways in Oak Ridge, Tennessee. The street tree inventory revealed that the street tree ecosystems had a high relative abundance of Acer rubrum (21.91%) and Pyrus calleryana (19.93%). Chemical, rather than physical, soil and site properties in street tree ecosystems had the greatest impact on street tree performance. Soils differed street by street in their biological, chemical, and physical properties but were not influenced by traffic rates. There were also differences in soil microbial biomass carbon (MBC) during the winter on streets based on their diversity of trees; however, the most diverse street was among the lowest in soil microbial biomass. Seasonally, the winter proved to have not only greater amounts of soil microbial biomass carbon and nitrogen (MBN), but significantly less extractable organic carbon (EOC) and nitrogen (EON) and total labile carbon (TLC) than that in the spring. Overall, this study provided insights into the post urbanization impacts on the street trees, soils, sites, and nutrient dynamics within street tree ecosystems of Oak Ridge.