Stress Arch Research Articles

A frictional arch model for pile-cap-beam-supported embankment

The pile-cap-beam-supported (PCBS) system can strength the soil arching effect of embankment, increase the lateral stiffness, bending resistance and vertical bearing capacity of the rigid pile, however there is no frictional soil arch model of PCBS embankment. In this paper, first a frictional arch model for PCBS embankment modified from Russell’s frictional arching model was proposed. The proposed model in this paper considers the algorithm of lateral pressure coefficient k and a changing critical height of soil arch. In this new method, the influence of pile spacing, filling properties, height and pile spacing on critical height soil arch was comprehensively considered. Second, a series of numerical cases were performed to verify the effectiveness of the proposed model and study the arching effect of PCBS embankment. By comparing the vertical stress and settlement between the theoretical and simulation results, the rationality of the proposed method to estimate the stress and critical height of arch was validated. The effectiveness of the proposed method was further validated by comparing loading efficacy to a reported case. Last, the stress and deformation of PCBS and pile-cap-supported (PCS) embankment were analyzed and the superiority of PCBS system in improving the performance of embankment was observed finally.

Application of FBG Sensing Technology for Real-Time Monitoring in High-Stress Tunnel Environments

In the process of tunnel construction, problems such as high-stress rockburst, large deformation of soft rock, water inrush and mud gushing, secondary cracking of linings, blasting interference, man-made damage, and mechanical damage are often encountered. These pose a great challenge to the installation of monitoring equipment and line protection. In order to solve these problems, the 2# inclined shaft of Muzhailing Tunnel in the Gansu Province of China, which exists under high stress, water bearing, and bias conditions, was taken as the research object in this paper. By assembling a string, drilling grouting and sealing, and introducing multiple modes of protection, new fiber grating sensor group installation and line protection methods were proposed. The automatic continuous monitoring of the deep deformation of surrounding rock and the automatic continuous monitoring of steel arch stress were realized. The field monitoring results showed that: (1) the fiber grating displacement sensor group could be used to verify the authenticity of the surface displacement results monitored by the total station; (2) the NPR anchor cable coupling support effectively limited the large deformation of soft rock and the expansion of surrounding rock in a loose circle, and the range of the loose circle was stable at about 1 m; and (3) the main influence range of blasting was at a depth of 0~5 m in surrounding rock, and about 25 m away from the working face. In addition, to secure weak links in the steel arch due to the hardening phenomenon, a locking tube was set at the arch foot. In the support design, the fatigue life of the steel was found to be useful as the selection index for the steel arch frame to ensure the stability of the surrounding rock and the long-term safety of the tunnel. The present research adopted a robust method and integrates a variety of sensor technologies to provide a multifaceted view of the stresses and deformations encountered during the tunneling process, and the effective application of the above results could have certain research and reference value for the design and monitoring of high stress, water-bearing, and surrounding rock supports in tunnels.

Reliability evaluation of reinforced concrete arch bridges during construction based on LGSSA‐SVR hybrid algorithm

AbstractDuring the cantilever casting process of reinforced concrete arch bridges with cantilever cast‐in‐situ method, it is difficult to select representative training samples for reliability analysis due to its complex structural system. Many random variables and large computational sample size, this paper proposes to solve the reliability indexes based on the combination of the improved sparrow search algorithm (LGSSA) and the support vector regression (SVR) method. Firstly, random variables are selected according to the actual situation of the bridge structure. Then representative training samples are designed to be substituted into the finite element model through the homogeneous method. The resultant data samples are used to fit the functional function by the support vector regression. Then combined with the penalized function method to transform the nonlinear optimization into the problem of solving the extreme value of the function. Based on the improved SSA to solve the extreme value of the final function. Finally the reliability index of the structure is obtained. With the background of reinforced concrete arch bridge of 200 m, the method is used to analyze the reliability of its buckling cable stress, arch stress, buckling tower deviation and structural system reliability during the cantilever casting process. The results show that the overall structural reliability of the arch ring during cantilever casting is 3.502–3.608. The indexes of buckling cable stress reliability are 3.806–6.784. The indexes of arch ring stress reliability are 4.379–7.562, and the indexes of buckling tower deflection reliability are 3.608–8.123.

Breaking law of overburden rock and key mining technology for narrow coal pillar working face in isolated island

When conducting retreat mining in segmented coal pillars, the dynamic evolution of stress and overlying strata structure is more complex than conventional working faces due to the influence of adjacent working faces. Understanding and mastering the dynamic evolution patterns of overlying strata structure after retreat mining in segmented coal pillar working faces is essential for guiding the safe recovery of coal pillar resources under similar conditions. Through statistical analysis of the types of residual coal and the mining techniques, the current research status of residual coal mining system in China has been summarized. Based on the safety recovery technology system for multi-type residual coal pillar resources at Zhaogu No.2 Mine, this paper focuses on narrow coal pillar working faces in sections with fully mined-out areas on both sides. By using research methods such as on-site measurement, theoretical analysis, numerical simulation, and engineering experiments, starting from the stress state analysis and evolution law of coal seam mining, the dynamic evolution law of the overlying rock structure of sectional coal pillars has been mastered. On this basis, a stress arch mechanical model of the mining area is constructed, and the working resistance of the support is calculated and determined, ensuring the safe recovery of the working face. The research results show that before the backfilling of the sectional coal pillar working face, the working face is affected by the overlapping mining of the goaf on both sides, presenting a “bimodal” stress distribution pattern, with a stress concentration coefficient between 1.78 and 3.2. After the extraction of segmented coal pillars, stress arches consisting of high-stress zones form along both the strike and dip of the working face. The structural support provided by stress arches undergoes a dynamic evolution process of “formation-development-elevation-stabilization” as the working face advances. Following the instability and rupture of the lower basic roof hinge structure, the stress-bearing structure shifts to the higher basic roof, continuing to provide support for the surrounding rock stress in the mining space of the working face. A stress arch mechanical model for the dip and strike of the mining area is constructed , and the shape characteristics of the overlying rock stress arch in the coal pillar working face is mastered. Based on the stress distribution law and stress arch evolution characteristics of the surrounding rock of the coal pillar working face, the maximum working resistance of the support in the working face is theoretically calculated to be 9153.48kN. Compared with the measured mine pressure data, the selected support effectively ensures the safety production of the working face.

Construction optimization of spatial arch bridges based on inverse hanging and RGA method

Form-finding and construction process are complex for spatial arch bridge. To facilitate the design and construction of spatial arch bridge, an algorithm with combination of inverse hanging and real-coded genetic algorithm (RGA) method is proposed. The experimental device suitable for inverse hanging experiment of spatial arch bridge is firstly proposed. The experimental results are compared with the numerical results to validate the accuracy of proposed form-finding algorithm. The validated results indicated that the error which is mainly caused by measure error is below 5 %. Then, the form-finding algorithm and RGA is combined to perform construction optimization for planar and spatial arch bridge. With the proposed optimization algorithm, the form-finding of spatial arch bridge is completed and the optimization of installation order of hangers can be performed based on the form-finding results. The tensioning force corresponding to different installation sequences is significantly different (546 kN and 177 kN). By using RGA, the max stress of arch is significantly decreased and generally below 100 MPa. The RGA is efficient in optimize the installation sequence. The control value of tension force of all hangers can be computed by using the RGA and reverse construction simulation. The nonlinear effect and the influence of geometrical size on tensioning force can be automatically considered. The results of this study indicate that the proposed algorithm is an efficient and accurate method for the construction optimization of spatial arch bridges.

The effect of overlying rock fracture and stress path evolution in steeply dipping and large mining height stope

To study the fracture instability characteristics and fracture mechanism of overlying strata in steeply dipping and large mining height stope, through the combination of physical simulation experiment, numerical calculation, theoretical analysis and field measurement, the correlation between the evolution of mining stress field and the fracture of overlying strata in large mining height stope under the effect of dip angle is analyzed, and the stress transfer path and the fracture mechanism of overlying strata are revealed. Finally, the influence mechanism of key strata on the evolution of the mining stress field of overlying strata is explained. The research shows that under the influence of gravity dip angle effect and mining height increase, the mining stress is non-equilibrium transferred and evolved in space, and the principal stress field presents the characteristics of partition evolution. The fracture trajectory of rock strata is multi-step and “八” shaped, and the inclined masonry structure and multi-step key strata form a cooperative bearing structure. The key layer of the ladder is the stress transmission structure between the caving zone and the stress arch, and the high stress in the overhanging area under the main roof is transmitted to the advanced roof. With the increase of dip angle, the height of the caving zone decreases, and the fracture range of ladder and principal stress arch decreases. The cracks in the middle and upper broken rock blocks increase, and the instability of the “high ladder rock layer” is easy to induce the simultaneous fracture of the “inclined masonry structure”, resulting in regional unbalanced instability and impact. The research results can provide some reference and guiding significance for the stability control of surrounding rock in longwall stope with steeply dipping.

Research on overburden structural characteristics and support adaptability in cooperative mining of sectional coal pillar and bottom coal seam

In the mining process of the II1 coal seam at Zhaogu No. 2 coal mine, a method of stratified mining is employed, leaving relatively wide coal pillars in sections. To enhance the resource recovery rate, the mine carries out the cooperative mining of the sectional coal pillars and the lower layer coal seam. The 14,022 cooperative working face of fully-mechanized and fully-mechanized top-coal caving at Zhaogu No. 2 coal mine is taken as the research object. Through numerical simulation, theoretical calculations, and on-site industrial trials, a comprehensive analysis of the overburden structural characteristics and the support adaptability at the working face is conducted. It is clarified that a stress arch bearing structure can be formed above the sectional coal pillars during cooperative mining, and this structure is controlled by key strata. The formation of a stress arch bearing structure in the overburden above the sectional coal pillars provides protection for the underlying mining area. A formula for calculating the working resistance of hydraulic supports under the stress arch in sectional coal pillar is derived. Based on these results, the working resistance of hydraulic supports in the coal pillar area is calculated and selected. Field application shows that the working resistance of the support is 10,000 kN in the fully-mechanized top-coal caving working face, and is 9000 kN in fully-mechanized working face, meeting the support requirements and ensuring safe mining at the working face. This study provides a valuable engineering reference for achieving cooperative mining of abandoned sectional coal pillars and lower layer coal seam in stratified mining method.

Assessing prestressed anchor cable support as ore pillar alternatives in stope span expansion: A case study

In large diameter long-hole (LDL) stopes, ore pillars are often set up in the rock drilling chamber to expand the span. However, after the ore pillars are blasted along with the stope, the stability of the roof is difficult to control, and collapse often occurs. This study introduced the idea of employing PAC support technology to replace the traditional ore pillar support and conducted site investigations, theoretical analysis, numerical simulations, and field tests to develop a technology for expanding the span of LDL stope based on prestressed anchor cable (PAC) support. Following a detailed investigation of pillar-supported LDL stope roof collapse events and geological conditions, a mechanical model for the stress arch considering the lateral stress coefficient was developed combining the failure characteristics and deep conditions, and the inverse relationship between the lateral coefficient of ground stress and the height of the stress arch above the opening was determined. Numerical simulation results demonstrate that the elliptical parabolic stress arch mechanical model has been verified, and PAC effectively controls roof stability, as evidenced by displacement and plastic zone response. Field tests were carried out utilizing PAC support, and monitoring results affirm the PAC support system's efficacy in stabilizing the roof. Using PAC to replace ore pillars resulted in a remarkable 29.8 % improvement in blast hole drilling efficiency and reduced ore dilution rate within the stope from 22.3 % to 14.2 %. This study serves as a reference for addressing analogous challenges in other mining operations.

Influence of cutterhead opening ratio on soil arching effect and face stability during tunnelling through non-uniform soils

Tunnelling has increasingly become an essential tool in the exploration of underground space. A typical construction problem is the face instability during tunnelling, posing a great threat to associated infrastructures. Tunnel face instability often occurs with the soil arching collapse. This study investigates the combined effect of cutterhead opening ratio and soil non-uniformity on soil arching effect and face stability, via conducting random finite-element analysis coupled with Monte–Carlo simulations. The results underscore that the face stability is strongly associated with the evolution of stress arch. The obtained stability factors in the uniform soils can serve as a reference for the design of support pressure in practical tunnelling engineering. In addition, non-uniform soils exhibit a lower stability factor than uniform soils, which implies that the latter likely yields an underestimated probability of face failure. The tunnel face is found to have a probability of failure more than 50% if the spatial non-uniformity of soil is ignored. In the end, a practical framework is established to determine factor of safety (FOS) corresponding to different levels of probability of face failure considering various opening ratios in non-uniform soils. The required FOS is 1.70 to limit the probability of face instability no more than 0.1%. Our findings can facilitate the prediction of probability of instability in the conventionally deterministic design of face pressure.

Study of Overlying Rock Structure and Intensive Pressure Control Technology of Island Longwall Panel in Extra-Thick Coal Seams

In response to the severe occurrence of mining pressure in the fully mechanized top coal caving face of the extra-thick coal seam and the problem of strong rock pressure caused by the remaining coal pillars in the mining area on the isolated island fully mechanized top coal caving face, taking the 8102 isolated island working face of Tongxin Coal Mine as the background and by using methods such as on-site measurement and numerical simulation experiments, the characteristics of roof mining in the island longwall panel of extra-thick coal seams were analyzed. Establishing a mechanical model for the mining stress and overlying rock stress arch of an isolated working face, the mechanical characteristics of the isolated working face under special conditions were obtained. The results show that the longwall panel no. 8102 has an asymmetric long-arm T-shaped covering layer structure before mining and a C-shaped covering rock structure during mining, which will exacerbate the degree of mining pressure manifestation in the working face. Directional high-pressure hydraulic fracturing was implemented in the gob of longwall panel no. 8102, and the pressure reduction effect of the advance support section of the gob was obvious, ensuring the safety of the working face.

Effect of lumbar lordosis angle on the development of lumbar spondylolysis in adolescent baseball players: A cross-sectional study

BackgroundLumbar spondylolysis (LS) is a lumbar vertebral arch stress fracture that often occurs in adolescent athletes, especially baseball players. An increase in lumbar lordosis angle (LLA) increases the compressive stress on the vertebral arch, influencing the development of LS. However, the effect of LLA on LS development in adolescent baseball players is unknown. Therefore, it is necessary to elucidate the risk factors that influence the development of LS. This cross-sectional study aimed investigate the effect of LLA on LS development in adolescent baseball players. MethodsPatients were male baseball players aged 11–18 years who visited an orthopedic clinic with a chief complaint of lumbar pain and underwent a magnetic resonance imaging (MRI) examination between January 1, 2018, and October 31, 2021. LLA was defined as the angle formed by the line parallel to the superior endplate of the L1 and S1. A person other than the data analyst measured LLA three times from the MRI, and the average value was used for data analysis. Logistic regression analysis was performed, with the presence or absence of LS as the objective variable and LLA, age, and previous pitching experience as explanatory variables. ResultsOf the 112 subjects included, 79 were in the LS group and 33 in the non-LS group. The LLA was 45.42 ± 8.19° in the LS group and 36.68 ± 8.26° in the non-LS group, with significant differences between the groups. Logistic regression analysis showed that LLA significantly differed with an odds ratio of 1.140 (95% confidence interval: 1.070–1.21), even after adjusting for age and previous pitching experience. ConclusionsLLA in adolescent baseball players was significantly greater in the LS group than in the non-LS group, which may influence the development of LS.

Evolution Law of Concrete Interface Stress of Rigid-Frame Arch under Construction and Its Impact on Ultimate Load-Bearing Capacity.

To study the evolution of stress on the ring and segment interfaces during the construction process of the concrete encapsulation of the main arch ring in a rigid-frame arch bridge, alongside its impact on the ultimate load-bearing capacity of the main arch ring, a 1:10 scale model experiment was conducted by taking the 600 m Tian'e Longtan Bridge as the prototype. The key cross-section concrete strain data were collected during the entire construction process of the main arch ring via fiber-optic strain sensors, which were used to investigate the stress evolution at ring and segment interfaces. ANSYS APDL was employed to simulate the ultimate bearing capacity under various loading conditions of two different finite element models, which were, respectively, formed segmentally and by single pouring. The results revealed that (1) after the closure of the concrete encapsulation of the main arch ring, the concrete stress in the cross-section exhibits significant stress disparities. At the same cross-section, the level of the web concrete stress can reach 76% of the floor concrete stress, while the roof concrete stress level is less than 20% of the floor concrete stress. (2) At the junction of two adjacent work planes, there are considerable differences in the stress levels of the concrete on both sides. After the closure of the main arch ring, the intersegment stress ratios of the floor, web, and roof concrete are 60~70%, 40~60%, and 0~5%, respectively. (3) Loading conditions remarkably affected the ultimate bearing capacity of the main arch ring. Under mid-span loading and 1/4 span symmetrical loading conditions, compared to single-pour concrete encapsulation, the ultimate bearing capacity of the main arch ring with concrete encapsulated by segmented and ring-divided pouring decreased by 19.16% and 5.23%, respectively, compared to single-pour concrete encapsulation. This suggests that the non-uniformity of stress distribution in the concrete sheath can lead to reductions in the ultimate bearing capacity of the arch ring.

Borehole Group Effect during Pile Foundation Construction in Soft Soil Areas

Existing projects indicate that a large number of pile boreholes formed via cement fly ash gravel (CFG) pile construction in soft soil could produce a borehole group effect in the absence of timely backfilling. The borehole group effect could cause ground settlement and threaten the safety of adjacent buildings, tunnels, and pipelines. However, the mechanism of the borehole group effect, causing serious deformation in surrounding soil, has seldom been studied, and there exists no simple simulation method to predict the borehole group effect. In this study, a case involving CFG pile boreholes in a soft soil area causing a significant settlement of surrounding buildings was introduced. Based on this case, a centrifuge test was designed to simulate the influence of a single borehole and multiple boreholes on the surrounding soft soil. The mechanism of the borehole group effect was investigated via centrifuge tests and the finite-element method. In the case of a single borehole, a horizontal circumferential stress arch and vertical stress transfer arch were formed in the soil, which effectively limited the shrinking deformation of the borehole wall. In the case of a large number of boreholes with a small spacing, the horizontal and vertical stress arches around the boreholes affected and weakened each other. As a result, the shrinking deformation of the borehole group was greater than that of the single borehole. In other words, the borehole group effect was found to cause serious deformation in the surrounding soil. To overcome the difficulty in the simulation of a large number of pile boreholes in engineering, the borehole-type conversion and multihole merging method was proposed. The simulation results indicated that the simplified method was reasonable.

Overburden Stress Arch Elevation Effect Induced by Roof Cutting and Destress Technique in Coal Mine Longwall Panel and Its Control Mechanism to Entry Surrounding Rock

Overburden Stress Arch Elevation Effect Induced by Roof Cutting and Destress Technique in Coal Mine Longwall Panel and Its Control Mechanism to Entry Surrounding Rock

Study on Rock and Surface Subsidence Laws of Super-High Water Material Backfilling and Mining Technology: A Case Study in Hengjian Coal Mine

Research on the rock and surface subsidence laws of super-high water material backfilling and mining technology can provide a scientific basis for liberating coal resources that are deposited under buildings, railways, and bodies of water. Using field measurements, numerical simulations, and theoretical analyses to study the geological mining conditions of the Hengjian Mine in Handan, Hebei Province, this research comprehensively analyzes the dynamic and static deformation laws of rock and surface subsidence, reveals the subsidence control mechanism, complements existing studies and helps improve the feasibility of new technology in engineering practices. This study shows that rock and surface subsidence values are smaller when the super-high water material backfilling and mining technology are used, and the surface movement parameters are smaller than those of the fully caving mining method. The backfilling material supports the rock load above the mining area and suppresses the rock and surface subsidence. In addition, the super-high water backfilling material limits the height of the developing stress arch above the mining area, thus reducing the range of deformation in the rock and surface movement. In engineering practice, the development of the stress arch can be controlled by increasing the backfilling rate and the strength of the backfilling material. With the above-mentioned discoveries, this research is of great significance to the promotion and application of super-high water material backfilling and mining technology and the liberation of deposited coal resources.

Model experiment and support optimization analysis of primary support arch cover excavation of large-section metro station in sandy mudstone stratum

The span and height of the Xietaizi metro station of Chongqing Rail Transit Line 18 are all larger than 20 m. The concept of “primary support arch cover” is adopted in the construction method, which aims to give full play to the bearing capacity of sandy mudstone, greatly improve the construction efficiency, and reduce the economic cost. In this paper, the model experiment of primary support arch cover excavation of large-section metro station in sandy mudstone stratum was carried out and the progressive failure process of the initial arch cover was revealed. It is found that the ground surface settlement is not strictly symmetrical about the station center, which is more significant in the case of the measuring points are far away from the central axis of the cavern. Since the support structure installed, the steel arch stresses and anchor axial forces at the inner and outer sides are in a rapid growth stage, and then shows a slow growth trend until stable. For the stresses at the inner and outer sides, the steel arch at the left arch shoulder is characterized by overall compression. The vertical displacements and convergence of the station are more prominent than the horizontal displacements and convergence, which indicates that the significance of control the settlement of the arch crown. The vertical convergence of the station is mainly caused by the settlement of the crown. When the level of loading is large, the number of longitudinal cracks will be increased as penetrating crack and the bulging phenomena will occur at the left arch shoulder of the secondary lining structure. Based on the numerical simulation, the whole dynamic procedure of construction is optimized from the demolition timing of temporary support. The vertical displacements and horizontal convergences for overall demolition schemes are smaller than those for stepping demolition with the excavation of middle guide holes.

Failure responses of rock tunnel faces during excavation through the fault-fracture zone

It is essential to cast light on the construction risks in tunnel excavations through the fault-fracture zone (FFZ). This study adopts the material point method (MPM) to simulate the failure responses of a rock tunnel face during excavation through the FFZ. A numerical study was conducted to compare a physical model test and validate the feasibility of using the MPM in simulating tunnel face failure. One hundred ninety numerical simulation cases were constructed to represent a rock tunnel excavation project with different site configurations. The simulation results suggest that the cohesion and the friction angle significantly influence failure responses. The tunnel cover depth can magnify the failure responses, and the FFZ thickness significantly affects the mobilized rock mass volume when the FFZ consists of a weak rock mass. The numerical simulation results suggest three deformation patterns: face bulge, partial failure, and slide collapse. The failure responses can be characterized by stress arch, slip surface, angle of reposing, and influence range. The insights suggested by the face failure responses during excavation through the FFZ can aid field engineers in determining the scope of possible damage, and in establishing emergency measures to minimize losses if such failure occurs.

Earthquake Response of Arch Dams including Hydrodynamic effect using ABAQUS

A simple arch dam [1] is analyzed to find responses due to an earthquake, including the hydrodynamic effect of the reservoir water. The simple arch shape dam was modeled as a monolith structure, assuming the linear behavior of dam concrete. The arch dam is modeled with finite elements. The hydrodynamic effect is considered as an added mass of water adhered to the dam’s upstream surface [2]. Natural frequencies and mode shapes are computed for the dam without water and the dam with water. Time history analysis of the dam is performed for the Kern County earthquake (1952), Taft component 111 acceleration time history. The added mass of water is calculated according to the Kuo 1982 [2] research paper. Various results containing Cantilever stresses, arch stresses, and deflections are shown and plotted. Analyses are performed with the help of the Abaqus Software.

Bolt-Cable-Mesh Integrated Support Technology for Water Drenching Roadway in Thick Coal Seam.

Aiming at the problems of large deformation and difficult control of the mining roadway water drenching in a thick coal seam, the principle of double-arch zoning cooperative surrounding rock control is studied by using the combined method of theoretical analysis, numerical simulation, and industrial experiment. The water-rock interaction of the surrounding rock of water-drenching roadway is proposed, taking into account the damage to the mechanical parameters of the surrounding rock caused by soaking water. The water-mechanical-damage coupling model for surrounding rock of a coal seam roadway is constructed, and is numerically solved by the code development using the FISH language. The principle of "high prestressed bolt-cable-mesh" zone coordinated control is revealed, and the existence of a compressive stress arch is verified by FLAC3D software. The three support schemes were compared and analyzed by numerical simulation software. We affirmed the bolt length of 2400 mm, spacing of 0.9 m, row spacing of 1 m, cable length of 7300 mm, and arrangement 3-2-3 as the optimal support scheme and applied this scheme in the Zhangcun Coal Mine. The results show that the maximum deformation of the roadway roof is 142 mm, and the ultimate convergence of the two sides is 83 mm. The surrounding rock has been effectively controlled.

Motion Characteristics of Collapse Body during the Process of Expanding a Rescue Channel

For the rapid construction of a rescue channel in the process of underground emergency rescue, a method for the expanded rescue channel in the collapse body is proposed and verified by a model test and a numerical simulation experiment. The motion characteristics and motion law of the expanded collapse body are analyzed on the basis of the mechanics of granular media, and a comparative simulation study on the main influencing factors of the collapse body motion is carried out. The results show that: (1) When the collapse body is expanded for a rescue channel, it will form three types of six relative slip planes. According to the position of the slip plane and the distribution of displacement, the collapse body can be divided into a direct displacement region, a stable region, and an indirect displacement region. (2) The expansion process can be divided into the initial start-up stage, the uplift stage, and the collapse stage, according to the formation time of the slip plane and the displacement law of the collapse body. (3) The results of the numerical simulation and the theoretical analysis of the granular media show that the dip angle of the slip plane is determined by the internal friction angle of the collapse particles, and the dip angles of the three slip planes are below θ1=90°−φ, θ2=45°+φ/2, and θ3=90°+φ/2. (4) The transverse scope and longitudinal distance is brought by the expansion increase with the increase in the expansion size, and the simulated dip angles of the slip plane are larger than the theoretical values due to the size effect. (5) In the expansion process, the strong force chain in the collapse body is concentrated in the stress arch above the expander device, and the failure and reconstruction laws of the stress arch at each stage are consistent with the formation of the slip plane and the uplift and instability law of the collapse body.