Roadway Width Research Articles

Reflection Propagation Law of Electromagnetic Waves in U-Shaped Roadway

To address the complex and space-constrained characteristics of underground coal mine roadways, this study proposes an electromagnetic wave reflection model based on the mirror image method. A U-shaped roadway model was designed and a relay node was established at the center of the roadway to simplify calculations. The point normal vector method was used to calculate the equations and boundary ranges of eight reflection planes. The valid reflection paths were determined by calculating the mirror points, counting the number of reflection lines, and evaluating their validity. The sensitivity of the number of valid reflection lines to the positions of the transmitting and receiving points relative to the corners was determined, and the reflected field strength at the receiving point was calculated. Its sensitivity to variables such as the distance between the relay node and the receiving point, antenna transmitting frequency, relative dielectric constant of the roadway walls, and width of the U-shaped roadway was studied. The simulation results showed that the number of valid reflection lines decreased with increasing distance from the transmitting and receiving points to the corners. The horizontal position of the transmitting point has a higher effect on the number of effective reflection lines than the vertical position, while the transmitting and receiving points are favorable for electromagnetic wave propagation when they are located in the center of the roadway. As the distance between the relay node and the receiving point increases, the reflection field strength attenuation at the receiving point will decrease with a larger roadway width, a smaller relative permittivity of the roadway walls, and a lower transmitting frequency of the antenna.

Mechanical characteristics and load-bearing effect of roadway anchorage composite carrier

Bolt support improves the stress state of the surrounding rock and forms an integral bearing structure inside the anchored surrounding rock. Therefore, it is of theoretical significance and practical application value to systematically study the mechanical mechanism and bearing characteristics of the anchorage composite carrier and elucidate the interaction mechanism between the bearing effect of the anchorage composite carrier and the stability of the roadway surrounding rock. In this paper, a mechanical model for the anchorage composite carrier is meticulously constructed through a fusion of theoretical analysis and advanced numerical simulation techniques. An in-depth exploration is conducted to elucidate the factors that significantly impact the bearing characteristics of the anchorage composite carrier. Specifically, the study examines the influence of supporting parameters, including bolt length, bolt diameter, bolt spacing, preload force, and roadway width, on both the effective formation and the thickness of the anchorage composite carrier. Based on the bearing effect of the anchorage composite carrier, aiming at the supporting problem of the cross-layer roadway (III811 interlocking roadway) in Luling Coal Mine of Huaibei Mining Co., LTD., the support technology application based on the bearing effect of the anchorage composite carrier is carried out, the support design scheme is optimized, the supporting effect is evaluated, and the evaluation method of the supporting effect and stability of the roadway is proposed. It is significant to apply support technology based on the bearing effect of anchorage composite carriers.

Dimensions of constructive elements of forest roads

Forest roads must be maintained in a condition that allows them to handle traffic loads at any given time, which is only achievable if their dimensions remain within the prescribed limits. The dimensions of the elements of the plan, profile, and cross-section of forest roads depend on factors such as soil type in a constructive context, the category of the forest road, and the type of vehicles that will use these roads. In this study, a forest road constructed on soil types IV, V, and VI was examined, and its dimensions were determined. The share of soil type in constructive sense is 63% of V category, 34% of IV category and 3% of IV category. The average width of the roadway is 6.11 m, with an upgrade of approximately 3% and a downgrade of 6.5%. The cross slope of the roadway is 3.1%, while the slope of the cut areas is 120% (1.2:1), and the slope of the fill areas is 86% (0.86:1). It was concluded that the forest road is in a condition capable of accommodating traffic load. However, attention should be given to the wider roadway width and the lower slopes of the cut and fill areas, as these may require adjustments to ensure efficiency and safety.

Exploring Factors Influencing Speeding on Rural Roads: A Multivariable Approach

Speeding is one of the main contributing factors to road crashes and their severity; therefore, this study aims to investigate the complex dynamics of speeding and uses a multivariable analysis framework to explore the diverse factors contributing to exceeding vehicle speeds on rural roads. The analysis encompasses diverse measured variables from Croatia’s secondary road network, including time of day and supplementary data such as average summer daily traffic, roadside characteristics, and settlement location. Measuring locations had varying speed limits ranging from 50 km/h to 90 km/h, with traffic volumes from very low to very high. In this study, modeling of influencing factors on speeding was carried out using conventional and more advanced methods with speeding as a binary dependent variable. Although all models showed accuracy above 74%, their sensitivity (predicting positive cases) was greater than specificity (predicting negative cases). The most significant factors across the models included the speed limit, distance to the nearest intersection, roadway width, and traffic load. The findings highlight the relationship between the variables and speeding cases, providing valuable insights for policymakers and law enforcement in developing measures to improve road safety by determining locations where speeding is expected and planning further measures to reduce the frequency of speeding vehicles.

Predicting the roadway width of forest roads by means of airborne laser scanning

Modern forestry relies on an extensive network of well-maintained forest roads. However, the trafficability of forest roads can be limited by poor construction or by insufficient load-bearing capacity caused by, for example, weather conditions. In all forestry operations, the forest roads should be able to support heavy vehicles during the transport of roundwood and harvesting machinery, so logistics must be carefully planned to ensure good road trafficability. To facilitate this planning, it is necessary to know the various characteristics of the forest road in terms of its width, structure and load-bearing capacity. Obtaining such information using remote sensing data would be beneficial. In this study, we used airborne laser scanning (ALS) data to assess the width of the roadway on forest roads. We developed several algorithms that were used to assess roadway width based on the cross-sectional data (derived with ALS) of the roads in 8-m long segments. The ALS echoes within the segments were classified into 20 cm wide strips which the algorithms then analyzed in a stepwise manner. Both height and intensity information from the ALS data were utilized. The algorithm results were then used as predictors in linear models to predict the roadway width. The main focus was on the road level, i.e., aggregated values from 25 different roads were used in model fitting. In terms of root mean square error (RMSE) values, accuracies of approximately 20–30 cm (or 7–10 %) were obtained for the predicted roadway widths with a separate validation data. This level of accuracy can be considered adequate given the characteristics of the ALS data used in the modelling. The results indicate that the presented approach has potential for practical applications to predict the width attributes of forest roads.

Research on the evolutionary patterns and control of surrounding rock superimposed stress field local area loading in double-layer Island face main roadway

Double-layer island working face main roadway coal pillars are affected by complex mining stress superposition, when different coal pillar width combinations, the surrounding rock stress field will produce different degrees of regional loading increase effect; the study of the surrounding rock stress field regional superposition loading increase law is meaningful to explaining the failure mode of the roadway and determining the critical control area. This study combines numerical simulation with on-site monitoring and other methods and draws the following conclusions: The superimposed loading increase law (“decreasing” → “increasing”) of the abutment pressure and deviatoric stress in the lower coal seam of the double-layer island working face during the mining; the type of the principal stress deflection in the advance working face region; and by obtaining the three types of development morphology of the deviatoric stress peak zone of the roadway and its corresponding nine evolution modes (one type of circular tube → four types of inverse hyperbolic body → four types of hyperbolic body) in the double-layered island working face mining. Indicated the critical reinforcement area corresponding to the main roadway when at different combinations of coal pillar widths; determined the main track roadway protective coal pillars width for 40 m and the shape of the roadway peak deviatoric stress zone is the inverse class hyperbolic body mode; according to the evolution mode of the peak deviatoric stress zone, determined the synergistic failure control program for the asymmetric critical zone of the roadway surrounding rock which is a targeted scientific support method; after the feedback of on-site monitoring and, the support program is reasonable and effective.

Urban Roadway in America: The Amount, Extent, and Value

Problem, research strategy, and findings We predicted the amount, share, and value of land dedicated to roadways within and across 316 U.S. primary metropolitan statistical areas. Despite the amount and value of land dedicated to roadways, our study provides the first such estimate across a broad range of metropolitan areas. Our basic approach was to estimate roadway widths using a 10% sample of widths provided by the Highway Performance Monitoring System and apply our estimates to the rest of the roadway system. Multiplying estimated widths by segment length and netting out double counting at intersections provided estimates of land area. We also matched roadway segments and areas to existing land value estimates and satellite-based measures of urbanized land. We found that a little less than a quarter of urbanized land—roughly the size of West Virginia—was dedicated to roadway. This land was worth around $4.1 trillion in 2016 and had an annualized value that was higher than the total variable costs of the trucking sector and the total annual federal, state, and local expenditures on roadways. Conducting a back-of-the-envelope cost–benefit analysis, we found that the country likely has too much land dedicated to urban roads. Takeaway for practice Federal, state, and local agencies dedicate substantial time, money, and resources to providing roadways. Even with relatively generous assumptions and no external costs from driving, however, we estimated that the average cost of expanding roadways exceeded the benefits by a factor of nearly three when accounting for land value. Policymakers should question policies focused on roadway expansion and consider options to reduce the amount of space dedicated to roadway in favor of more housing, offices, and other land uses. In addition to our findings, we provide a novel data set that academics and policymakers can use to draw their own conclusions about the state of America’s urban roadways.

Study on Critical Width of Semi-Coal Rock Roadway of Shallow-Buried Thin Coal Seam Based on Coal Side Self-Stabilization

In the context of a shallow-buried thin coal seam, the surrounding rock deformation in the semi-coal rock roadway is comparatively small, resulting in self-stabilization of the two sides of the roadway without the need for support when the roadway is below a critical width. This study focuses on the transportation roadway of the 2107 working face in the Anzhe Coal Mine, employing a combination of laboratory tests, field tests, theoretical analyses, and numerical simulations. A mechanical model for the layered roof of the semi-coal rock roadway in a shallow-buried thin coal seam is developed, along with a calculation formula for determining the critical width of such roadways. The study also initially examines the correlation between the critical width and factors such as the tensile strength of the roof, the buried depth of the roadway, and the thickness of the immediate roof strata under conditions where the coal sides of the roadway are self-stabilizing. The results showed the following. (1) The calculation formula has good applicability for typical shallow-buried mine roadways in the Niuwu mining area and shallow-buried semi-coal rock roadways with coal thickness below 0.7 m under similar geological conditions. The critical width is related to the tensile strength of the roof, the buried depth of the roadway, and the thickness of the immediate roof strata. The degree of influence is determined by the thickness of the immediate roof strata > the tensile strength of the roof > the buried depth of the roadway. Among these, the tensile strength of the roof, the thickness of the immediate roof strata, and the critical width are basically in a positive exponentially increasing relationship, and the buried depth of the roadway and the critical width are basically in a negative exponentially decreasing relationship. (2) The on-site measurement of the loose circle on both sides of the roadway revealed that the rock mass loose circle had a thickness of 0.2 m, while the coal loose circle had a thickness ranging from 0.6 m to 0.7 m, aligning closely with the results obtained from theoretical calculations. The thickness of the coal loose circle on both sides served as the basis for determining the critical width of the semi-coal rock roadway in the shallow-buried thin coal seam. The calculated critical width of the roadway was 2.9 m, whereas the actual width measured was 2.4 m. Consequently, the two sides of the roadway are deemed capable of self-stabilization in the unsupported state. (3) Following the optimization of the support scheme, engineering analysis indicates that the roof and floor exhibit a maximum convergence of 46.3 mm, while the two sides show a maximum convergence of 18.4 mm. It is observed that the surrounding rock of the roadway satisfies the safety requirements for production. This study can provide theoretical support and a scientific basis for the stability discrimination of two sides and surrounding rock control of semi-coal rock roadways in shallow-buried thin coal seams under similar conditions.

Ultimate Bearing Capacity of Weak Foundations under Coal Pillars

In many underground coal mines, a seam is underlain by weak floor material, and the load-carrying capacity of a pillar may be limited not by its own strength but by the bearing capacity of the floor. It has been proposed that bearing capacity may be estimated by formulae such as those of Terzaghi for structural footings on soil, but that approach is generally not valid because, for the slip surfaces assumed in the derivations of the formulae, the rock rises out of the floor beneath adjacent pillars. In the limiting equilibrium analysis proposed here, the distance to the side of a pillar to which a slip surface extends can be constrained according to the roadway or bord width. Examples are shown of the computation of bearing capacities of both homogeneous and multilayer dry and fully saturated floors, and results compared with those of elastoplastic finite element analysis. An approximate comparison with bearing capacities according to Terzaghi's formula for a strip footing is also presented for the hypothetical cases of wider roadways for which the assumed slip surfaces do not extend under adjacent pillars. For the cases considered, there is satisfactory agreement with Terzaghi’s analysis and good agreement with the results of finite element analysis. However, only one finite element analysis was carried out, and it remains to be seen whether such agreement is consistently achieved for ranges of floor strength parameters and horizontal stress.

Stability prediction of roadway surrounding rock using INGO-RF

In order to more accurately classify the stability of roadway surrounding rock and identify dangerous areas in a timely manner to prevent roadway collapse and other disasters, an INGO-RF roadway surrounding rock stability prediction model is proposed. This model combines the improved Northern Gok algorithm (INGO) and Random Forest (RF) based on the analysis of influencing factors of roadway surrounding rock stability. First, three strategies were employed to enhance the Northern Gob algorithm (NGO): Logistic chaotic mapping, refraction reverse learning, and improved sine and cosine. Subsequently, INGO was utilized to optimize the number of decision trees and the minimum number of leaf nodes for RF species in order to improve the prediction accuracy of RF. Secondly, a data set consisting of 34 groups of roadway surrounding rock data is selected. The input indexes of the model include roof strength, two-wall strength, floor strength, burial depth, roadway pillar width, ratio of direct roof thickness to mining height, and surrounding rock integrity. Meanwhile, surrounding rock stability is considered as the output index. Particle swarm optimization backpropagation neural network (PSO-BPNN), genetic algorithm optimization support vector machine (GA-SVM), Sparrow search algorithm optimization RF (SSA-RF) models were introduced to compare the prediction results with the INGO-RF model, and the results showed that: INGO-RF model has the best performance in the comparison of various performance indicators. Compared with other models, the accuracy rate (Ac) in the test set has increased by 0.12∼0.4, the accuracy rate (Pr) has increased by 0.07∼0.65, and the recall rate (Re) has increased by 0.08∼0.37. The harmonic mean (F1-Score) of the recall rate increased by 0.08∼0.52, the mean absolute error (MAE) decreased by 0.1428∼0.4285, the mean absolute percentage error (MAPE) decreased by 7.15%∼28.57%, and the root mean square error (RMSE) decreased by 0.1565∼0.3779. Finally, the data on surrounding rock conditions of roadways in multiple mining areas in Shanxi Province were collected to test the INGO-RF model. The results indicate that the predicted outcomes closely align with the actual results, demonstrating a certain level of reliability and stability. It shows that it can better meet the practical needs of engineering and avoid the occurrence of mine disasters.

Numerical Simulation Study on the Deformation Patterns of Surrounding Rock in Deeply Buried Roadways under Seepage Action

To reveal the deformation patterns of the surrounding rock in deeply buried straight-wall arch-shaped roadways under seepage action, this study, based on an FLAC3D numerical simulation and classic elastoplastic theory, investigates the influences of surrounding rock classification, roadway burial depth, pore water pressure, and roadway cross-sectional dimensions on the deformation of surrounding rock. A multivariate regression prediction model for rock deformation was established based on the numerical simulation conclusions, and the correctness of the conclusions was verified through comparative analysis. Correlation analysis of various factors with rock deformation was conducted, ranking their impact as follows: pore water pressure > roadway burial depth > surrounding rock classification > roadway height > roadway width. The research results can provide guidance for the construction and support of deeply buried roadways under seepage action.

Determining of Appropriate Passenger Car Unit Values Due to a Change in Effective Width of Roadway

Legitimately, the passenger car equivalent value is determined based on the type and width of the road as well as the traffic volume. Interestingly, the effective width of roadway often varies due to land topography conditions and level of side friction. Theoretically, the number of survey posts should be determined based on road geometric and environmental conditions because traffic volume is a reflection of the choice of speed. Unfortunately, due to limited funds, traffic volume, travel speed and ride friction surveys were carried out at 1 survey point. As a result. the recommendations for strategies and/or traffic management and engineering techniques could be bias. This study aims to calculate the impact of differences in the effective road width on the equivalent value of passenger cars using the Speed Method. For this reason, a speed survey was carried out on a number of arterial roads in the Kupang urban area. It was found that changes in the effective width of road lanes have a significant impact on changes in motorbike speed so that the use of passenger car equivalent value for motorcycle should be based on the result of field survey, instead of a standardized value as it was recommended by Indonesian Highway Capacity Guide

Presentation of artificial neural network models based on optimum theories for predicting accident severity on rural roads in Iran

This study focuses on predicting the number and severity of rural accidents using nine accident-related variables by the multi-layer perceptron (MLP) approach as a type of artificial neural network modeling method. The models were developed using the input parameters of shoulder width, roadway width, roadside hazard, access density, passing zone ratio, speed limit, pavement condition index, shoulder rumble strips, and centerline rumble strips. MLP models were created based on accident data that occurred from 2019 to 2020 on the Tehran–Qom and Tehran-Saveh rural roads in Iran. In order to achieve the highest accuracy, twenty MLP models have been built with various structures. The MLP model, consisting of a multilayer feedforward network with hidden sigmoid and softmax output, has been used in this study. In this regard, an attempt was made to present an optimum theory to select the best model. The most accurate model was chosen based on the R-value and root mean square error (RMSE), mean absolute error (MAE), f, SD, and R2. Results indicated that the R-value obtained from the optimum model was 0.912, representing the accurate performance of the selected model. In addition, access density, roadside hazard, and roadway width were identified as the most significant variables.

Determination of Pedestrian LOS for Crosswalks at Intersections - A Case Study in Shivamogga City

The main objective of this research is to identify the variables that affect the level of service (Los) of pedestrians at intersections both (signalized and unsignalized) in shivamogga city. Based on the experiences of the pedestrians at the individual in intersections. A walker’s questionnaire survey was done to gather level of service of pedestrians in terms of protection, comfort, and convenience for every crossing at signalized & unsignalized intersections. Additionally, a video graphic method was employed to scan each crosswalk at the chosen three signalized and two unsignalized intersections. Pedestrian crossing time, pedestrian waiting time, pedestrian holding area, roadway width, and crosswalk surface condition were the key variables taken into account for the construction of the model. For each crossing, a considerable number of pedestrian ratings were collected, these ratings were used as the dependent variables in the analysis. In order to estimate the pedestrian level of service for each intersection's crosswalk, a stepwise multiple linear regression analysis utilizing SPSS software is used to construct a pedestrian Los model.

Capacity drop at the bus stop on multilane divided urban roads under mixed traffic conditions

Time headway characteristics are of great importance for planning and design of roadway. The present study determines time headway distribution pattern of vehicular stream at various urban roads and evaluate drop in capacity of roadway section having curb-side bus stops. Field data for present study was collected at 8 different locations on four-lane and six-lane divided sections in the cities of Warangal and Hyderabad in India. The mean time headway of heterogeneous vehicles fitted to various headway distributions for estimating capacity of road section. The factors affecting the capacity have been identified as bus frequency, dwell time, and the average roadway width lost. Percentage reduction in capacity (PRC) is determined to develop regression model. Further, speed-flow diagrams were developed using field observed traffic flow data for determining parameters free-speed, critical speed, and roadway capacity on selected section. After comparing capacity values obtained from two methods, the study determined avg. time headway of vehicular stream under the traffic flow at capacity and free flow conditions. The study also finds capacity value of bus stop section using methodology provided in Indo-HCM (2017). The PRC values estimated based on Indo-HCM guidelines are found to be significantly higher than those estimated by the proposed PRC model. It is due to the Indo-HCM guideline considering only one parameter i.e. bus frequency. The study finds, in addition to bus frequency the dwell time, roadway width lost, and presence of an extra lane also influences the drop in capacity of bus stop section on multilane divided urban roads.

The problem of organizing traffic safety on two-lane main streets of district importance

The article examines the state of accidents in the Krasnoyarsk Territory and in the city of Krasnoyarsk, in particular. Since collisions predominate among road accidents, one of the accident-prone areas was selected where the largest number of collisions were recorded in 2022. During the analysis, it was established that the location of the vehicle on the roadway does not correspond to the design scheme, therefore, on the selected road alignment, the complexity of the intersections was assessed using a point system and the safety indicator Ka was determined. Measures aimed at reducing accidents on a specific road section are proposed. Keywords traffic safety, roadway width, vehicle, markings, traffic flow

Speed Reduction Capabilities of Two-Geometry Roundabouts

Several types of modern roundabouts are alternatives to standard ones. They are either in use or at the development stage today. One such intersection is the two-geometry roundabout. Its circulatory roadway has an elliptical outer edge and a circular inner edge that is defined by a circular central island resulting in variable circulatory roadway width. The investigation presented in this paper aims to determine the influence of this variable width on the design of other geometric elements and its impact on roundabouts’ speed reduction capabilities. There is not enough experimental data collected to make a comparison to other roundabout types, so this investigation is based on computer simulations and speed estimations. The investigation is conducted on 40 four-legged single-lane roundabout schemes. These were designed in the Autodesk AutoCAD 2021 software through computer simulations of vehicle movement and the resulting swept paths of a tractor with a semi-trailer generated by the Autodesk Vehicle Tracking 2020 software. The results show that truck aprons must be included in the design of two-geometry roundabouts with a major axis between 18 and 25 m to achieve appropriate circulatory roadway widths, personal car path deflection, and the resulting relative speed and speed consistency.

Evaluation of Electric Vehicle-Dependent Strategy in Addis Ababa, Ethiopia Transport System

This paper assesses the transport system of Addis Ababa, Ethiopia, taking factors such as the number of vehicles, roadway width, speed of vehicles, longitudinal grade, and proportion of both fuel and electrical vehicles by dividing vehicles into seven classes, namely, car, minibus, small bus, coach, small truck, heavy truck, and truck trailer, to determine CO2 emission, CO emission fuel consumption, and electric consumption in addition to the percent to replace ICE vehicles. After selecting eight representative road sections in Addis Ababa city, input data was collected from both primary and secondary sources. Simulation of urban mobility (SUMO) is used to model the existing road transport system and two other scenarios, cases being 20% and 40% replacement of internal combustion engine vehicles by electric vehicles. Among the vehicle types studied under this paper, the SUMO results show that coaches are with the highest CO2 emission, releasing an average amount of 28.442 grams of CO2 every time step, while cars are with the lowest CO2 emission value of 6.542 grams. Minibuses are the top CO emitters, releasing an average of 0.420 grams of CO every time step, and truck trailers emit the smallest CO emission, 0.025 grams. Regarding electric consumption, the truck trailer is the vehicle type with the highest electric consumption, with a value of 2.282 kwh (watthour) consumption every time step, and cars are the least electricity-consuming vehicles, with a value of 0.151 kwh. The fourth point is fuel consumption; besides the high CO2 emission, coaches’ consumption of fuel is leading by 8.946 grams, and cars use 2.087 grams of fuel every time step. Totally, public transport vehicles are responsible for higher emissions and huge fuel consumption. Therefore, if our transport system encourages the penetration of electric vehicles into the road transport system, a healthy and energy-efficient environment is reserved. Again, from a financial and environmental standpoint, the replacement of 40% of ICE vehicles by EVs enhances us with reduced costs and a green environment.

Road Safety Criteria for Mid-Block Pedestrian Crossing Facility and Application of ITS Technologies

This paper describes an attempt made to evaluate the pedestrian's road crossing facility at midblock to relate with pedestrian road crossing behaviour and identify the variables influencing pedestrian road crossing decisions. The decision of pedestrians on road crossing depends on many other elements like yielding behaviour of a driver, vehicle speed, roadway width, traffic volume etc. Pedestrians road crossing data collected through videographic survey at Kozhikode city, Kerala, India were used to evaluate the pedestrian crossing facility. Regression model has been developed considering the pedestrian waiting time as dependent variable and vehicle speed and volume as independent variable. Further, a computational tool is developed to derive suitable criteria for regulating the number of pedestrian phases based on the percentage of vehicles in the queue formation for varying levels of interruptions and vehicle arrival rate. The criteria has been derived such that the negative force exerted by vehicles and drivers during pedestrian road crossing to a minimum level, through the implementation of signal control using Intelligent Transport System (ITS) technologies. Further, the queuing analysis results helps to identify the criteria for proposing grade-separated crossing based on the threshold value of the percentage of vehicles in the queue formation. From the queuing analysis, it was found that, the percentage of vehicle in queue has been increased from 19.44% to 38.89% for the arrival rate of 1200v/h when the number of pedestrian interruptions per hour is increased from 20 to 40. Also, it is observed that when the arrival rate increases from 1200 to 1800 v/h the percentage of vehicle in queue increases 19.44% to 77.78% for 20 number of pedestrian interruptions. The prediction tool developed may help the transportation policymakers and highway officials to evaluate the field conditions and to identify suitable control measures for the pedestrian facility with improved pedestrian safety and vehicular traffic efficiency.

Mechanics Model of Floor Heave: Case Study on Thin Coal Seam with Soft Roof and Floor

The fully mechanized caving roadway’s floor heave has a significant impact on the stability of the narrow coal pillars, the filling body next to the roadway, as well as the entire roadway. Significant floor heave necessitates extensive maintenance and rebuilding work, which has a negative impact on the mine’s regular operations. The costs of sustaining and maintaining the roads are significantly increased by production. In this study, a mechanical model of the floor heave of the road along the goaf is established using the Winker elastic foundation theory model. The mechanical model of the floor heave of the roadway is confirmed when combined with engineering cases. The findings of the study indicate that there is almost no deformation of the side floor of the roadside support and the solid coal. The floor deformation of the roadway area exhibits non-positive symmetry and a “parabolic” characteristic. Roadway width, burial depth, and roadway floor heave all have linearly positive correlations, but elastic modulus of the floor, burial depth, and highway floor heave all have negatively exponential correlations. The maximum deformation of the floor heave, which has a maximum value of 628 mm, is close to the side of the roadway support body; the theoretical model’s maximum value for the floor heave after 100 days of actual deformation monitoring is 645 mm. Between the maximum value and the maximum value as measured, there is a 2.6% error. The paper has important guiding significance for explaining the mechanism of floor heave in goaf roadway and controlling the deformation of the roadway floor.