Plastic Stress Research Articles

Surface Nanocrystallization and Numerical Modeling of 316L Stainless Steel during Ultrasonic Shot Peening Process

Surface nanocrystallization of metals and alloys via high-frequency ultrasonic shot peening (USP) can significantly increase the mechanical properties of the materials. However, the relationship between the external process parameters and the internal microstructure of the materials is still unclear and an accurate numerical model to simulate the USP process is urgently required for better control of the grain refinement process. In this study, we successfully realized surface nanocrystallization of 316L stainless steel using USP with an ultrasonic frequency and amplitude of 20 kHz and 50 μm, respectively. The microstructure evaluation of 316L stainless steel during USP was revealed. We established a finite element numerical model to simulate the high-frequency USP process and calculated the plastic strain and stress distribution of 316L stainless steel during the grain refinement process. We investigated the effects of the ultrasonic frequency, working distance, and ultrasonic amplitude on the plastic strain and stress distribution on the materials using the finite element simulation method. The dynamic behavior of the shot during the USP process was studied using a high-speed camera, and the FE simulation results agreed well with the experimental results. We also investigated the impact of multiple shots during the USP process by the high-speed camera observation and FE simulation. Research results indicate that high-frequency USP is an effective method to obtain large-scale bulk nanocrystalline materials and the finite element simulation can help materials scientists and engineers to better understand the relationship between the process parameters and microstructure evaluation of 316L stainless steel.

Analysing of nano-silica usage with fly ash for grouts with artificial neural network models

When grout is used to penetrate voids and cracks in soils and rock layers, easy and effective pumping of the grouts is vital, especially for grouting works during geotechnical improvements. For this reason, improving the rheological parameters of cement-based grouts and increasing their fluidity are important for effective grouting injection. In this study, an experimental investigation and analysis using artificial neural network (ANN) models were used to discover how nano silica (n-SiO2) together with fly ash affects the rheological behaviour of cement-based grouts. The effects of nano silica (n-SiO2) additions at different contents by mass (0.0%, 0.3%, 0.6%, 0.9%, 1.2% and 1.5%) on the plastic viscosity and yield stress values of cement-based grouts incorporating fly ash as a mineral additive at different amounts (0% – as a control, 5%, 10%, 15%, 20%, 25% and 30%) were investigated. Using the experimental data obtained, a feed-forward (FF) back-propagation (BP) multi-layer perceptron (MLP) artificial neural network (ANN) was developed to predict the plastic viscosity and yield stress of cement-based grouts with nano silica nanoparticle additives. The ANN model developed can predict the plastic viscosity and yield stress values of cement-based grouts containing nano silica nanoparticle-doped fly ash with high accuracy.

Analysis and Modeling of Stress-Strain Curves in Microalloyed Steels Based on a Dislocation Density Evolution Model.

Microalloyed steels offer a good combination of desirable mechanical properties by fine-tuning grain growth and recrystallization dynamics while keeping the carbon content low for good weldability. In this work, the dislocation density evolution during hot rolling was correlated by materials modeling with flow curves. Single-hit compression tests at different temperatures and strain rates were performed with varying isothermal holding times prior to deformation to achieve different precipitation stages. On the basis of these experimental results, the dislocation density evolution was evaluated using a recently developed semi-empirical state-parameter model implemented in the software MatCalc. The yield stress at the beginning of the deformation σ0, the initial strain hardening rate θ0, and the saturation stress σ∞—as derived from the experimental flow curves and corresponding Kocks plots—were used for the calibration of the model. The applicability for industrial processing of many microalloyed steels was assured by calibration of the model parameters as a function of temperature and strain rate. As a result, it turned out that a single set of empirical equations was sufficient to model all investigated microalloyed steels since the plastic stresses at high temperatures did not depend on the precipitation state.

Singularity analysis of linear hardening V-notch by asymptotic expansion coupled BEM

In this paper, a general numerical method by the asymptotic expansion coupled the boundary element method (CBEM), considering the singular term and the higher order terms, is developed to analyze the complete singular stress field of linear hardening elastic–plastic material with a V-notch. The method firstly transforms the singularity analysis for the governing equation of the V-notch tip into an ordinary differential eigenvalue equation, which is then solved by the interpolating matrix method. Then, the complete singular stress field and the notch stress intensity factors (SIFs) can be obtained by coupling the asymptotic expansion of the elastic–plastic singular stresses at the V-notch tip with the conventional boundary elements method for the remaining region of the structure. Two types of examples are analyzed for the V-notch problem of linear hardening material. It is shown that the elastic–plastic singular stress field can be evaluated by the equivalent Young’s modulus and Poisson’s ratio. The proposed new approach is found to be accurate and effective in evaluating singular stress fields in a V-notch structure with linear hardening material.

In situ stress inversion and fracture characteristics around local fault in deep heterogeneous strata

The southeast Sichuan in China is a key area for deep shale gas exploration. However, shale gas exploration in deep heterogeneous strata is greatly affected by in situ stress. Faults caused by tectonic movement strongly change the distribution of in situ stress. Inversion and prediction of in situ stress have become an important research hotspot in the field of resource exploitation. Based on the geological structure evolution and experimental data, the boundary stress iterative inversion method is used to inverse the in situ stress field of deep heterogeneous strata containing shale gas reservoirs, and the fracture characteristics around local fault are analyzed by fracture mechanics theory. The research shows that the stress field has the characteristics of non-uniform distribution under the influence of fault, and there is obvious stress concentration and deflection of principal stress direction around the fault. And magnitude and direction of stress are affected by the internal friction angle of the fault zone and the formation depth in different tectonic periods. Through the analysis and calculation of the plastic strain and stress intensity factors, it can be inferred that the cracks will propagate at the terminal portion of the fault. The research is important to guide engineering for the adjustment of resource exploitation scheme.

Partitioned coupling framework to combine a kinematic hardening plasticity model and a creep model for structures in a high‐temperature environment

AbstractThe present study proposes a partitioned coupling framework for the implementation of a combined kinematic hardening plasticity and creep model. In the present framework, plastic and creep implicit stress integrations are performed alternately and iteratively until convergence in a partitioned coupling manner. This approach enables us to tractably implement a constitutive model that combines a plasticity model and a creep model in the program. The present framework was applied to the combination of the Ohno–Wang plasticity model and the Norton–Bailey creep model for numerical examples. The numerical examples demonstrated the capability of the present framework in analyzing realistic structures at high temperature with the consideration of both plasticity and creep.

Examining the effect of Debris Flow on Oil and Gas Pipelines Using Numerical Analysis

This article examines the impact of debris flow on semi-exposed pipelines to determine the plastic deformation and stresses by considering pipe-debris flow interaction. A 3-D finite element approach was adopted to study the mechanical behavior of pipelines subjected to debris flow. Integration of pipeline property (thickness) with debris flow intensity (impact pressure and angle) was also considered in a finite element numerical model for semi-exposed. The analysis showed that the impact angle between 35° and 75° with an impact pressure of 200 kPa and 250 kPa significantly affected the stability and integrity of the pipeline. There was a slight impact of wall thickness on the stability of the pipeline due to the passive soil resistance. Maximum plastic deformation of 124 mm was encountered in the case of 35° impact angle, which was 3% more than the deformation observed at 20° impact angle. Moreover, large distribution of von mises stresses was observed, as 1390 Mpa, 1450 Mpa, 1440 Mpa, and 1440 Mpa for impact angles of 20°, 35°, 75°, and 90° in the impacted zone of the pipeline in each set of analysis. Shear failure of the pipeline was observed during the analysis as von misses’ stresses were more than the yield stress (520 Mpa) of the pipeline. The developed model in this study can be utilized for further research and will be a basis for designing pipelines crossing through mountainous regions.

Structural Modeling of REBCO VIPER Cable for High-Field Magnet Applications

A structural model has been developed for the REBCO-based VIPER cable [1], which is designed for high magnetic field applications. In this work, structural finite element analysis (FEA) is used to simulate the stresses incurred within the REBCO tape stacks under the following conditions: (1) bending to 1 m diameter (2) cooling down to 77 K and (3) repeated transverse electromagnetic Lorentz loadings up to 1600 kN/m. The effect of solder impregnation onto the stress state of the tapes was studied via a set of friction coefficients of 0.02 (perfect-slip), 0.2 (metal-to-metal contact), and 1 (no-slip). For bending, high friction between the tape-stack and solder results in high axial strain in the tape-stack which may lead to I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> degradation. During thermal cooldown, the stress on the tape-stack is negligible. However, the differential in thermal contraction between the copper and stainless-steel jackets leads to the formation of a small gap that may cause mechanical instability. Under cyclic Lorentz loading, a higher friction coefficient reduces the deformation of the cable by restricting the relative sliding between the neighboring tapes, which results in a more uniform stress distribution and a lower peak stress. A lower friction coefficient results in larger deformation of the solder and stack and a higher peak stress. In addition, due to the accumulated plastic deformation and stress concentration in the solder, both the averaged von Mises stress and the peak stress of the outermost four tapes increase with each of the first three loading cycles. These results may explain the early-stage degradation observed in the experiments conducted on VIPER cables (Z. S. Hartwig <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> , 2020).

Strength of Partially Encased Steel-Concrete Composite Column for Modular Building Structures.

Modular structural systems have been used increasingly for low- and mid-rise structures such as schools and apartment buildings, and applications are extending to high-rise buildings. To provide sufficient resistance and economical construction of the high-rise modular structural system, the steel-concrete composite unit modular structure was proposed. The proposed composite unit modular system consists of the composite beam and the partially encased nonsymmetrical composite column. The outside steel member of the composite column has an open section, and is manufactured using a pressed forming procedure so that easy joining connecting work and manufacturing cost reductions are possible. However, the design methods are complicated due to the inherent nonsymmetrical properties of the section. Therefore, in this study, the focus was made on the strength evaluation and development of design methods for the partially encased nonsymmetrical steel-concrete composite column. Four full-scale specimens were constructed and tested. The experimental study focused on the effect of the slenderness ratio of the column, eccentricity, and the through bars on the strength of such columns. Additionally, the P–M interaction curve to estimate the strength of the proposed composite column under general combined loading was developed based on the plastic stress distribution method. The results indicate that the through bars are needed to delay the local buckling and distribute the loading uniformly throughout the composite column. Finally, the proposed design methods provide a conservative strength prediction of the proposed composite column.

Use of rheological plastic models to describe the flow behaviour of unconventional chocolate masses

The chocolate mass behaves like a typical non-Newtonian plastic liquid defined by the yield stress and the plastic shear stress. The rotary rheometer with a cone-plate spindle system was chosen to determine the flow properties of chocolate masses. The effect of shear stress on shear deformation rates was measured at a temperature of 40 °C in an ascending mode from 1 s&lt;sup&gt;–1&lt;/sup&gt; to 500 s&lt;sup&gt;–1&lt;/sup&gt; for chocolate samples [white chocolate (WC), ruby chocolate (RC), and caramelised Amber chocolate (AC)]. Plastic models, according to Casson, Bingham and Herschel-Bulkley, were used for the mathematical description of this dependence. The Herschel-Bulkley model was evaluated as the most suitable mathematical model for describing the flow behaviour of unconventional chocolate masses. The Herschel-Bulkley model was chosen based on a high value of the coefficient of determination R&lt;sup&gt;2&lt;/sup&gt; and a low value of the sum of the square error estimate (SSE). The non-Newtonian plastic behaviour was confirmed, and the yield stress was determined for all types of tested chocolate masses.

Experimental and numerical investigations on square CFST column to U-shaped steel-concrete composite beam joints with internal T-shaped diaphragms

An innovative joint detail with internal T-shaped diaphragms for concrete-filled steel tubular (CFST) columns to U-shaped steel-concrete composite (USCC) beams is proposed in this study. Five beam-column joint specimens are tested under cyclic loading to evaluate the seismic performance. The test parameters are the connection form between top reinforcing bars (re-bars) and steel tubes, the total cross-section area of top re-bars, and the strengthening method for the joint. Test results show that welding the U-shaped steel directly to the steel tube may lead to premature fracture of bottom flanges in the connection vicinity; the H-steel corbel and the strengthening plate help delay the fracture of bottom flanges, and increase the joint's positive bending capacity effectively. The joint shows superior negative bending capacity, and the plastic stress distribution assumption can be utilized to calculate the joint's negative bending capacity with reasonable accuracy. While the joint shows lower positive bending capacity when premature fracture of bottom flanges occurs, thus the elastic stress distribution assumption is suggested for calculating the joint's positive bending capacity. Additionally, a finite element (FE) model is developed and verified. The effects of axial load ratio, the total cross-section area of top re-bars, the width to thickness ratio of steel tubes, and the thickness of the strengthening plate on the joint's bending capacity are investigated numerically. It is found that the joint's bending capacity decreases with the increase of axial load ratio and width to thickness ratio of steel tubes. The strengthening plates increase the positive bending capacity, and the top re-bars enhance the negative one.

Hydration and rheology of activated ultra-fine ground granulated blast furnace slag with carbide slag and anhydrous phosphogypsum

In this study, two different ultra-fine ground granulated blast furnace slag referred to as GS (i.e., by dry-winnowing method) and WS (i.e., by wet-grinding method) were obtained, and the hydration and rheology of activated ultra-fine ground granulated blast furnace slag (activated-BFS) with carbide slag and anhydrous phosphogypsum (AG) as combined activator were systematically investigated by means of setting time, workability, rheological behavior, compressive strength, autogenous shrinkage, electrical resistivity, SEM, XRD and TG-DTG. The results showed that the limiting factor is the BFS type, and not the AG dosage in terms of setting time, and their rheological behavior fitted with H–B model. WS and increase in AG dosage significantly reduced the plastic viscosity, shear stress and yield stress of activated-BFS pastes. The WS presented higher initial reaction activity that generated more hydrates in the early age, restricting the further hydration of BFS particles especially when AG dosage exceeded 10%, thus leading to the different compressive strength development trends between mixtures containing WS (WS/A) and GS (GS/A). The compressive strength of GS/A mixtures increased with increasing AG dosage and reached 39.9 MPa at 3 days, while WS/A first increased and then decreased. The activated-BFS with carbide slag and AG is technically feasible to be employed as cementitious materials in the production of concrete.

Potential of Whole-Body Vibration in Parkinson's Disease: A Systematic Review and Meta-Analysis of Human and Animal Studies.

Simple SummaryExercise has shown to have a positive impact on both motor and non-motor functions in Parkinson’s Disease patients. However, particularly in later stages of the disease, reduced cognitive function and motor capacity may lead to an inability to stay physically active. Therefore, alternative strategies for patients with Parkinson’s Disease are necessary to minimize burden for patients, their families and public health care. Whole-Body Vibration could be such an alternative. Whole-Body Vibration is an exercise or treatment method in which subjects are exposed to a mechanical vibration while sitting, standing or exercising on a vibrating platform. Whole-Body Vibration is currently used for physiotherapy, sports and rehabilitation purposes. Whole-Body Vibration treatment is interesting because it affects both the body and brain. The potential of Whole-Body Vibration for, specifically, Parkinson’s Disease patients should be clarified for further application. For this purpose, we conducted an extensive systematic review of the articles investigating the effects of Whole-Body Vibrations (1) on animals and humans with Parkinson’s Disease and (2) on neuropathological Parkinson’s Disease mechanisms. The results show some potential of Whole-Body Vibration for Parkinson’s Disease patients. The recommendations provided by this review can be used by researchers and rehabilitative practitioners implementing Whole-Body Vibration as a treatment for Parkinson’s Disease patients.(1) Background: When the severity of Parkinson’s Disease (PD) increases, patients often have difficulties in performing exercises. Whole-Body Vibration (WBV) may be a suitable alternative. This systematic review aims to clarify if WBV shows potential as rehabilitative therapy for PD patients. (2) Methods: We searched several databases for controlled trials investigating the effects of WBV (1) on PD populations and (2) PD neuropathological mechanisms. We included both human and animal studies and performed meta-analyses. (3) Results: The studies on PD populations (14 studies) show an overall significant, but small, effect in favor of WBV (Hedges’ g = 0.28), for which the effects on stability (Hedges’ g = 0.39) and balance (Hedges’ g = 0.30) are the most prominent. The studies on the neuropathological mechanisms (18 studies) show WBV effects on neuroinflammation (Hedges’ g = –1.12) and several specific WBV effects on neurotransmitter systems, growth factors, neurogenesis, synaptic plasticity and oxidative stress. (4) Conclusions: The effects of WBV on human PD patients remains inconclusive. Nevertheless, WBV protocols with sufficient duration (≥3 weeks), session frequency (≥3 sessions/week) and vibration frequency (≥20 Hz) show potential as a treatment method, especially for motor function. The potential of WBV for PD patients is confirmed by the effects on the neuropathological mechanisms in mostly non-PD populations. We recommend high-quality future studies on both PD patients and PD mouse models to optimize WBV protocols and to examine the neuropathological mechanisms in PD populations.

Micro-mechanism for nanocrystallization of laminated Fe-based metallic glass foil side-milled

Although various achievements were made in past years to improve the mechanism of cystallization of metallic glass using annealing or deformation processes, the relationship between the micromechanisms of nanocrystalline formation in metallic glass while milling has not been thoroughly investigated. To elaborate on the connection between plastic deformation, stress, temperature, and nanocrystallization, the laminated Fe-based metallic glass foil (FMGF) was machined by side-milling with and without ultrasonic vibration. Plastic deformation can accelerate nucleation and therefore nanocrystallization with respect to phase separation in FMGF at high temperatures. The nanocrystal distributions in the FMGF milled with ultrasonic vibration is cyclical along the milling direction. The temperature of the nucleation and growth mechanism associated with phase separation is higher than that of the nucleation mechanism based on the linked-flus model. The results provide insights on the effects of plastic deformation and high temperature in the crystallization of FMGF.

Influence mechanisms of plasticity and horizontal stress difference on the fracture propagation in plastic reservoir rocks: a 3D XFEM-based plastic fracturing model

Influence mechanisms of plasticity and horizontal stress difference on the fracture propagation in plastic reservoir rocks: a 3D XFEM-based plastic fracturing model

Multi-Scale Modelling of Plastic Deformation, Damage and Relaxation in Epoxy Resins.

Epoxy resin plasticity and damage was studied from molecular dynamic simulations and interpreted by the help of constitutive modelling. For the latter, we suggested a physically motivated approach that aims at interpolating two well-defined limiting cases; namely, pulling at the vanishing strain rate and very rapid deformation; here, taken as 50% of the speed of sound of the material. In turn, to consider 0.1–10-m/s-scale deformation rates, we employed a simple relaxation model featuring exponential stress decay with a relaxation time of 1.5 ns. As benchmarks, deformation and strain reversal runs were performed by molecular dynamic simulations using two different strain rates. Our analyses show the importance of molecular rearrangements within the epoxy network loops for rationalizing the strain-rate dependence of plasticity and residual stress upon strain reversal. To this end, our constitutive model reasonably reproduced experimental data of elastic and visco-elastic epoxy deformation, along with the maximum stress experienced before fracturing. Moreover, we show the importance of introducing damage elements for mimicking the mechanical behavior of epoxy resins.

The Direct Strength Method for first generation trapezoidal steel sheeting under Interior One Flange and Interior Two Flange web crippling

Trapezoidal steel sheeting is a popular product in the built environment, especially for roofing and cladding. However, at a support the webs of the sheeting may fail due to concentrated force, referred to as web crippling. In this paper it is investigated whether the Direct Strength Method (DSM) can be used to predict this failure. First, an experimental programme, carried out in the past, is selected for its sheet section dimensions, materials, span lengths, and load bearing plate widths which were varied systematically. Two distinct failure mechanisms occurred: the yield arc and the rolling mechanisms. Based on the experiments, in this paper a finite element model is developed to simulate Interior One Flange (IOF) and Interior Two Flange (ITF) web crippling, and a very good correlation is obtained with the experiments. Subsequently, the simulations are used to predict the buckling load (via the first positive Eigenvalue), the yield load (via first plastic strains or stress extrapolation), and the ultimate load for each experiment and additional cases. In addition, for each failure mechanism, an existing theoretical model is used to predict the first order elasto-plastic mechanism initiation load. Six different DSM equations are calibrated for both IOF and ITF web crippling, using the above different buckling and yield loads. For IOF cases, the use of the IOF first positive Eigenvalue for the buckling load, and the first order elasto-plastic mechanism initiation load, results in the best correlation and coefficient of variation. For ITF cases, the ITF Eigenvalue and same yield load shows the best results. Excluding the rolling mechanism, the DSM correlates equally (IOF) or better (ITF) with the numerical results than the AISI S100-16 design rule. Thus, the DSM, as a generalized slenderness approach, is suited for IOF and ITF web crippling of first generation trapezoidal steel sheeting. Furthermore, it could be considered to allow for the use of the well performing FE models explicitly by the codes—e.g. enabling manufacturers to create tables of strength.

Flexural behavior of prestressed concrete-filled steel tubular flange beams

This research presents a numerical and analytical investigation on the structural characteristics of concrete-filled steel tubular flange beams (CFSTFBs) prestressed using steel strands under bending. CFSTFBs are found to benefit from higher flexural and shear strength compared to those of I-section beams with flat flanges. The geometrical configurations of these sections provide them with higher web local buckling resistance due to a larger flange depth-to-width ratio. A large number of existing structures, constructed with steel–concrete composite beams, need to be retrofitted due to many factors such as loss of strength as a result of service loads and environmental conditions. A potentially economical and feasible approach to strengthening these beams is upgrading them using steel prestressing strands. The finite element (FE) approach was utilized to develop a three-dimensional numerical model considering both material and geometrical nonlinearity. Accordingly, the effects of concrete strength, tubular flange shape and dimension, steel yield stress, and quantity and eccentricity of strands were included in the analysis. A simplified model, on the basis of the plastic stress distribution method (PSDM), was used to estimate the ultimate moment capacity. In order to visualize the influence of steel and concrete strength and tubular flange size on the moment capacity of CFSTFBs, several artificial intelligence (AI) algorithms were employed and a partial dependence analysis was also conducted accordingly. The ultimate capacities obtained by analytical and FE models, considering the effect of confinement, were verified by comparing the predictions with the results from experimental studies. Both analytical and FE results indicated that the prestressing strands are significantly capable of enhancing the stiffness and strength of CFSTFBs under flexural loading. It was demonstrated that the tube geometric properties can significantly control the overall performance of prestressed CFSTFBs. The results also indicated a negligible effect of the concrete compressive strength.

Determination of the Plastic Stress–Strain Relationship of a Rupture Disc Material with Quasi-Static and Dynamic Pneumatic Bulge Processes

Rupture discs, manufactured using a hydraulic or pneumatic bulge process, are widely used to protect vessels from over-pressuring. The stress–strain relationship of the material in the bulge process plays a major role in understanding the performance of rupture discs. Moreover, both the theoretical analyses and numerical simulations of rupture discs demand a reliable stress–strain relationship of the material in a real bulge process. In this paper, an approach for determining the plastic stress–strain relationship of a rupture disc material in the bulge process is proposed based on plastic membrane theory and force equilibrium equations. Pressures of compressed air and methane/air mixture explosions were used for the bulge pressure to accomplish the quasi-static and dynamic bulge processes of tested discs. Experimental apparatus for the quasi-static bulge test and the dynamic bulge test were built. The stress–strain relations of 316L material during bulge tests were obtained, compared, and discussed. The results indicated that the bulge height at the top of the domed disc increased linearly with an increase in bulge pressure in the quasi-static and dynamic bulge processes, and the effective strain increased exponentially. The rate of pressure rise during the bulge process has a significant effect on the deformation behavior of disc material and hence the stress–strain relationship. At the same bulge pressure, a disc tested with a larger pressure rise rate had smaller bulge height and effective strain. At the same effective stress at the top of the domed disc, discs subjected to a higher pressure rise rate had smaller effective strain, and hence they are more difficult to rupture. Hollomon’s equation is used to represent the relationship between the effective stress and strain during bulge process. For pressure rise rates in the following range of 0 (equivalent to quasi-static condition), 2–10 MPa/s, 10–50 MPa/s, and 50–100 MPa/s, the relation of stress and strain is σe = 1259.4·εe0.4487, σe = 1192.4·εe0.3261, σe = 1381.2·εe0.2910, and σe = 1368.4·εe0.1701, respectively.

Research on Theory and Technology of Floor Heave Control in Semicoal Rock Roadway: Taking Longhu Coal Mine in Qitaihe Mining Area as an Example

Abstract As one of the most common disasters in deep mine roadway, floor heave has caused serious obstacles to mine transportation and normal production activities. The third section winch roadway in the third mining area of Qitaihe Longhu coal mine has a serious floor heave due to the large buried depths of the roadway and the semicoal rock roadway, and the maximum floor heave is 750 mm. For the problem of floor stability, this paper establishes a mechanical model to analyze the stability of roadway floor heave by analogy with the basement heave of deep foundation pit. It provides a model reference for analyzing the problem of roadway floor heave. Aiming at the problem of roadway floor heave in Longhu coal mine, the roadway model is established by using FLAC3D, and the roadway model after support is established according to the on-site support measures. Through the analysis of the distribution of roadway plastic area, stress nephogram, and displacement field simulation results, the results show that the maximum displacement of roadway roof and floor after support is reduced by 15% and 23%, but the maximum floor heave is still 770 mm, which is close to the measured floor heave of roadway. In order to solve the problem of roadway floor heave and integrate economic factors, this paper puts forward three support optimization schemes, simulates the support effect of each scheme, and finally determines that scheme 3 is the best support optimization scheme. Compared with that under the original support, the amount of floor heave is reduced by 81%, and the final amount of floor heave is 150 mm, which can meet the requirements of roadway floor deformation. The results provide a scheme and guidance for roadway support optimization.