Failure Mechanisms and Support Technologies in Deep Soft Rock Roadways

Deep roadways excavated in soft, weak, or highly fractured rock masses are subject to complex failure processes driven by high in situ stresses, time-dependent deformation and mining-induced disturbances. Initially, excavation generates stress redistributions that can exceed the residual strength of the shallow rock, leading to tensile cracking, shear failure and progressive fragmentation of the surrounding rock. Under high stress, plastic zones evolve in characteristic “butterfly” shapes and propagate into the walls, roof and floor, while rheological (creep) behaviour in argillaceous or coal seams further aggravates convergence over time. Floor heave, roof collapse and sidewall bulging often occur simultaneously, posing significant safety hazards and operational bottlenecks. In response, a range of support technologies has been developed and refined. Rock bolting and cable anchors remain the backbone of most systems, supplemented by steel sets and wire mesh to form load-bearing shells. Grouting techniques—including cementitious and chemical injections—reinforce weak strata and seal off fracture networks. More recent advances exploit zonal reinforcement, combining shallow anchors with deep bolts or cables to integrate a composite bearing structure. Jet grouting has emerged as a promising method for in situ soil-rock mixing to create stiff columns around the excavation, while yielding supports and compression arches distribute loads more evenly across the lining. Together, these measures aim to stabilise the surrounding rock, control large deformations and ensure the safe, efficient operation of deep underground roadways worldwide.

Research from Nature Portfolio

No recent Nature Portfolio content available.

Failure Mechanisms and Support Technologies in Deep Soft Rock Roadways publication trend

The graph below shows the total number of articles in failure mechanisms and support technologies in deep soft rock roadways across all publications each year (not limited to Nature Index journals).

Technical terms

Surrounding rock: The intact and fractured mass enveloping an excavation, whose mechanical response governs failure and support needs.

Large deformation: Excessive displacement of tunnel boundaries, often exceeding support capacity and leading to progressive loss of stability.

Rock bolting: Anchoring technique in which steel rods are inserted into boreholes and tensioned to reinforce and bind rock layers.

Grouting: Injection of cementitious or chemical fluids into voids or fractures to improve rock mass cohesion and stiffness.

Plastic zone: Region around an excavation where rock has yielded and undergone irreversible deformation under stress redistribution.

Rheological behaviour: Time-dependent deformation (creep) of rock or coal under sustained load, contributing to gradual convergence.

References

1. Support technologies for deep and complex roadways in underground coal mines: a review. International Journal of Coal Science & Technology (2014).
2. A Study of the Large Deformation Mechanism and Control Techniques for Deep Soft Rock Roadways. Sustainability (2018).
3. Research on the failure process and stability control technology in a deep roadway: Numerical simulation and field test. Energy Science & Engineering (2020).
4. Stability Control for the Rheological Roadway by a Novel High-Efficiency Jet Grouting Technique in Deep Underground Coal Mines. Sustainability (2019).
5. Failure Mechanism for Surrounding Rock of Deep Circular Roadway in Coal Mine Based on Mining‐Induced Plastic Zone. Advances in Civil Engineering (2018).
6. Failure analysis and control technology of intersections of large-scale variable cross-section roadways in deep soft rock. International Journal of Coal Science & Technology (2022).