Related Experiment Video
Updated: Jul 9, 2025

A Uniaxial Compression Experiment with CO2-Bearing Coal Using a Visualized and Constant-Volume Gas-Solid Coupling Test System
Published on: June 12, 2019
A case study on new high-strength temporary support technology of extremely soft coal seam roadway
Zhijun Xu1, Chong Li2, Yue Cao1
1School of Mining Engineering, China University of Mining and Technology, Xuzhou, China.
Abstract:
One of the main challenges in excavating roadways is implementing temporary supports that are powered by hydraulics and have high strength. The current temporary support system lacks active support and often causes separation between the top plate and the layer below. It is crucial to control the initial separation of the roadway roof for the stability of the surrounding rock, especially on roadways with loose and soft rock. This research focuses on the A4027 return airway in Sail Six Mine. The issues with the temporary support system in this airway have been identified. The concept and principle of using hydraulically driven, high-strength temporary support technology are proposed. A mechanical analysis model is created to study the stacked roof in the temporary support region, and the critical conditions for delamination of the top plate are determined. The relationship between the delamination difficulty parameter Q, the distance between temporary supports L, and the strength of the temporary supports q is quantified. Numerical simulation using Flac3d is used to model the relationship between the strength of the temporary supports and the deformation and stress of the rock on the roof. The overall strength of the temporary supports for the A4027 return airway is determined to be 10 kN/m2, with a distance of 2 m between the temporary supports. Hydraulically driven, high-strength temporary support devices are developed and tested for their strength. Field trials are conducted as well. The results show that the initial separation of the top plate is improved and that the support effect in the temporary support region is significant. The maximum separation of the top plate during excavation is only 34 mm, and the sinking of the top plate does not exceed 68 mm. This effectively limits the deformation of the surrounding rocks in the very soft coal seam, providing valuable insights for other roadways with similar conditions.
More Related Videos
08:03Advanced Self-Healing Asphalt Reinforced by Graphene Structures: An Atomistic Insight
Published on: May 31, 2022
09:00Visualization of Failure and the Associated Grain-Scale Mechanical Behavior of Granular Soils under Shear using Synchrotron X-Ray Micro-Tomography
Published on: September 29, 2019
Related Concept Videos
Design Example: Managing Concrete Workability
Types of Cement I
Type I (Ordinary Portland Cement) is widely used for general construction where special properties are not required. It has moderate sulfate resistance and heat of hydration.
Type II (Modified Cement) offers moderate resistance to sulfate attack and a lower rate of heat development compared to Type I. It is suitable for structures in...
Abrasion Resistance of Concrete
One such test is the revolving disc test, where three plates...
Toughness and Hardness of Aggregate
Design Example: Joints in Concrete Pavements
Contraction joints are typically formed by sawing a groove into the concrete shortly after it has hardened. This creates a weakened vertical plane, deliberately encouraging cracking at...
Posttensioned Masonry Walls
Post-tensioned masonry walls use high-strength steel rods or flexible tendons to enhance the strength and efficiency of masonry structures. These elements are securely anchored to the foundation and extend vertically either within the cores of the masonry units or between the masonry wythes. The construction process involves building the wall with these tensioning elements in place and allowing the mortar to fully cure.
Following the curing process, the tensioning begins. Steel rods are...