Peak Shear Stress Research Articles

Experimental and Numerical Study on Nonlinear Shear Behavior and Constitutive Model of Deep Shale Laminae Planes

The direct shear tests showed that the degradation of unevenness and waviness of the laminae plane is the primary reason for the dynamic decrease in shear strength. A shear constitutive model was proposed which considers the scale effect and the asperity geometry of the unevenness and waviness of the laminar plane. The evolution of the shear strength and stiffness with a normal stress and scale effect during the shearing of shale laminae planes was explored. The results show that high normal stress aggravates the stiffness hardening of laminae planes and forms larger peak shear stress and peak shear displacement. At the lab scale, the increase in the unevenness wavelength has a hardening effect on the shear stiffness and strength. The small-scale unevenness contributes most to the shear strength of shale laminae planes at the lab scale. At the field scale, the increase in the waviness wavelength has a softening effect on the shear stiffness and strength.

Shear behavior of cold region clay-concrete interface under temperature-controlled direct shear tests

The shear properties of the permafrost-structure interface play a crucial role in analyzing the performance of engineering structures in cold regions. Direct shear tests were carried out on the permafrost-concrete structural interface by means of self-improved and optimized temperature-controlled direct shear apparatus to investigate the effects of temperature, moisture content and freeze-thaw cycles. Test results were used to establish a shear characteristic model under coupled influence of temperature and humidity. Preparation of specimens consisting of precast C30 concrete blocks and soil samples taken from borehole cores of the pile foundation of the Middle Bridge No. 3 on the road from Sai Township to Qiuluo Village, Sakya County, Tibet, China, and were treated to different effective confining pressure (σn = 300 kPa, 400 kPa, 500 kPa and 600 kPa), different temperatures (T = −20 °C, −15 °C, −5 °C, 0 °C, 5 °C, 15 °C, and 20 °C), different moisture contents (ω = 5 %, 10 %, 15 %, and 20 %), and different numbers of freeze-thaw cycles (N = 0, 1, 3, 5, 7and11) from −15 °C to 15 °C, test results are given and analyzed. The peak shear stress (τp) is significantly higher than the residual stress (τr) at negative temperature, τp is greater than 1.5 times to 3.2 times of τr. τp is greatly affected by temperature changes, τp under negative temperature is 17 % higher than that under positive temperature, because the water in the soil freezes at negative temperatures, forming a concrete-ice-soil bond interface, which increases the peak strength of the interface. While τr is insensitive to temperature changes. At negative temperatures, the cohesion (c') changes less with increasing water content (ω), and the effect of ω on the external friction angle (φ′) is more significant. At positive temperature, the cohesion decreases with increasing ω, and the effect of ω on the external friction angle is not significant. When N < 5, the cohesion increases with the increase of N; when N = 5, c' reaches the maximum value; when N > 5, c' decreases with the increase of N. Moreover, regardless of the type of shear behavior, the first five freeze-thaw cycles have the greatest impact on the external friction angle. Compared with the sample that has not experienced freeze-thaw cycles, when N = 5, the total decrease in the external friction angle of the sample is 25.6 %.

Experimental and Numerical Investigations on the Slate Shearing Mechanical Behavior

Multi-scale assessment of shear behavior in the tunnel carbonaceous slate is critical for evaluating the stability of the surrounding rock. In this study, direct shear tests were conducted on carbonaceous slates from the Muzhailing Tunnel, considering five bedding dip angles (β) and four normal stresses (σn). The micro-mechanism was also examined by combining acoustic emission (AE) and energy rate with PFC2D Version 5.0 (particle flow code 2D Version 5.0 software) numerical simulations. The results showed a linear relationship between peak shear stress and normal stress, with the rate of increase inversely related to β. Cohesion increased linearly with β, while internal friction angle and AE activity decreased; the energy release rate is 3.92 × 108 aJ/s at 0° and 1.93 × 108 aJ/s at 90°. Shearing along the preset fracture plane was the main failure mode. Increased normal stress led to lateral cracks perpendicular to or intersecting the shear plane. Cracks along the bedding plane formed a broad shear band with concentrated compressive force, and inclined bedding was accompanied by a dense tension chain along the bedding plane.

INNOVATIVE EXPERIMENTAL TESTING PROGRAM OF DIRECT SHEAR TEST IN SOIL MECHANICS

The research work aims at analyzing for the first time the data set obtained on cohesive soil samples following the publication of the Romanian Invention Patent RO 134239. The standard test method for the direct shear test provides the shear strength parameter – internal friction angle in consolidated drained condition - of either undisturbed or remolded soil samples forcing the shear plane at the midsection of the sample in the horizontal direction. The samples are provided in parallelepipedal shape (6 cm x 6 cm x 2 cm) and the displacement rate in horizontal direction is 0.1 mm/min. The new equipment patented in Romania changes the direction of shearing, from horizontal to vertical, and the soil samples are of cubic shape (6 cm x 6 cm x 6 cm). The experimental program involves testing both the parallelepipedal and cubic samples using the same motorized mechanism, with simultaneous readings from their respective micro-comparators. The UU test is performed without allowing consolidation and shearing at 1.0 mm/min. For the CD test, samples are consolidated under vertical loads for 24 hours before shearing at 0.1 mm/min. The shear stresses for cubic samples were higher than those for parallelepipedal samples, with residual stresses reflecting this trend. For cubic samples, both the peak and residual shear stresses trend lines indicated higher cohesion (c) and lower internal friction angle (𝜙) for UU tests and CD tests in contrast to parallelepipedal samples in both testing conditions. The innovative testing program allows for variability in shear strength parameters along the soil failure surface in both natural and compacted soil structures. This differentiation divides the soil condition into drained and undrained states at the initiation, emergence points, and the point of maximum depth along the failure surface. This approach is significant for accurately assessing soil shear resistance and potential failure mechanisms. The study's findings suggest a nuanced approach to parameter selection for slope stability analysis, ensuring accurate representation of both cohesion and internal friction in stability models.

Interface mechanical properties of CFRP-seawater sea sand concrete under simulated seawater immersion

In this study, the interfacial mechanical properties of carbon fiber-reinforced polymer (CFRP) sheet reinforced seawater sea sand concrete (SSSC) in simulated seawater immersion environment were studied. The results present that the interface bearing capacity of CFRP-SSSC decreases significantly after seawater immersion. The decreasing rate increases greatly with the extending of immersion periods. Seawater immersion also affects the failure mode of interface between CFRP and SSSC, which leads to the damaged surface expanding from the base layer of concrete to the junction section of resin and aggregate. The distribution of strain and stress along the bonding direction presents the load transfer from the loading end to the free end. The shear stress peak locates near the loading end and decreased about 15–20 % due to seawater immersion as a result of the deterioration of the interfacial property. The analysis on the microstructure of CFRP-SSSC interface proves that the chemical ions in seawater causes the hydrolyzation of epoxy resin adhesive layer. The CFRP-SSSC interface presents a lower interfacial bonding properties than CFRP reinforced normal concrete (NC). The improvement of strength grade of concrete from C30 to C50 increases the bonding properties of the CFRP about 9–12 % and mitigates the influence of seawater immersion. The obtained bond-slip curve indicates that the seawater immersion decreases the interface ductility. A modified Popovics model is applied to predict the bond-slip curve and presents a high fitting degree.

Enhancing shear strength of sandy soil using zein biopolymer

Ecofriendly stabilization using various biopolymers has been explored to enhance the soil strength and the stability of geotechnical structures. This study investigates the improvement of shear strength characteristics in sandy soils treated with a novel protein-based biopolymer, zein. Poorly- and well-graded sands are treated with three different biopolymer contents (1, 2, and 3 %) and cured for 1–28 days. Direct shear tests are conducted under four normal stresses to evaluate the shear behavior and strength parameters of treated and untreated sands. The treated sands exhibit higher peak shear stress and more brittle behavior than the untreated sands due to the formation of biopolymer gel between the soil particles. The treated specimens show a greater improvement in shear strength over longer curing periods, with variation based on soil gradation. After curing for 28 days, apparent cohesion and internal friction angle significantly increase, from 8.1 to 257 kPa and from 26 to 45.4⁰, respectively. Poorly graded sands demonstrate a greater improvement in shear strength compared to well-graded sands, owing to the higher pore spaces available for biopolymer filling and bonding. Thus, incorporating zein biopolymer can significantly enhance the shear strength characteristics of sandy soil, providing a sustainable alternative for soil stabilization in geotechnical engineering.

A novel cohesive interlayer model considering friction

To understand the influence of friction on the shear-slip behavior of heterogeneous brittle composites, a novel cohesive interlayer model that can effectively capture the friction effect was proposed based on the classical Park-Paulino-Roesler model. Meanwhile, the unified potential energy function governing the interface tangential and normal behaviors was introduced to realize the mechanical interaction between Mode I fracture and Mode II fracture, and a smooth friction growth function was added in the elastic deformation stage for calculating the accurate contact pressure and friction force. Furthermore, the capability of the proposed model in addressing unloading and reloading was improved, and the fracture energy can vary accordingly during cyclic loading. To verify the effectiveness of the proposed model, it was examined by modelling the shear behavior of a masonry wallette. The results show that the relative error of the proposed model is 14.92% which is much lower than those of the other three pre-existing models when calculating the displacement corresponding to peak shear stress. Meanwhile, in terms of peak shear stress and initial displacement at residual stage, the relative errors of the proposed model are only 1.82% and 5.04%, respectively, indicating the high accuracy. Besides, the tangent stiffness determined by the second-order integration of the potential energy function is also continuous and smooth, which ensures the effective convergence of the proposed cohesive model.

Experimental investigation of permeability evolution and progressive damage of sandstone in the complete process of direct shear

Permeability evolution and damage behavior under shearing conditions are critical for reliable predictions of rock seepage characteristics during excavation and a correct assessment of their impacts on the occurrence of natural or induced hazards. However, publications concerned with this problem have been poorly issued so far. The primary objective of this study is to innovatively investigate permeability evolution and damage behaviors of sandstone in the complete process of direct shear. Several groups of red sandstone specimens are deformed in direct shearing using a newly modified servo-controlled direct shear apparatus to measure permeability evolution and monitor acoustic emission (AE) activities with damage under various normal stress conditions. The morphology of the rupture surfaces is scanned using a 3D laser scanner after tests. According to our experimental results, the locus of the shear stress-displacement curve is found to be closely associated with microcrack progressivity. The initial permeability in advance of shearing test and the peak permeability appearing after the peak shear stress decrease with the increasing normal stress. The minimal and maximum permeability values exhibit a lag-effect with respect to the turning and the peak points on the shear stress-displacement curve. Furthermore, a palpable surge is found in the interevent time function during shearing, which can be a potential indicator for early warning of catastrophic rupture of brittle rock materials under shearing or compression. The joint roughness coefficient (JRC) values in the direction of shearing deformation for each normal stress case are more significant than those in the direction perpendicular to the shear displacement. The impacts of our obtained results are potential ramifications for permeability control in rock engineering projects.

Numerical analysis of ultrasound-mediated microbubble interactions in vascular systems: Effects on shear stress and vessel mechanics

The present study concerns the numerical modeling of microbubble oscillation within an elastic microvessel, aiming to enhance the safety and efficacy of ultrasound-mediated drug delivery and diagnostic imaging. The success of such applications depends on a thorough understanding of microbubble–vessel interactions. Despite some progress, the critical impact of the stabilizing shell around gas core has remained underexplored. To address this, we developed a novel numerical approach that models the stabilizing shell. Additionally, there is novelty in modeling consequent vascular deformation in response to complicated spatiotemporal microbubble oscillations. The novel approach was implemented for shear stress evaluation as a critical factor in vascular permeability. Finally, our unique approach offered novel insights into microbubble–vessel interactions under diverse acoustic conditions. Results indicated substantial impact of shell properties and acoustic parameters on induced shear stress. With a fourfold increase in acoustic pressure amplitude, 15.6-fold and sixfold increases were observed in maximum shear stress at 1 and 3 MHz, respectively. Also, the peak shear stress could reach up to 15.6 kPa for a shell elasticity of 0.2 N/m at 2.5 MHz. Furthermore, decreasing microvessel/bubble size ratio from 3 to 1.5 increased maximum shear stress from 5.1 to 24.3 kPa. These findings are crucial for optimizing ultrasound parameters in clinical applications, potentially improving treatment outcomes while minimizing risk of vessel damage. However, while our model demonstrated high fidelity in reproducing experimental observations, it is limited by assumptions of vessel geometry and homogeneity of vessel properties. Future work can improve our findings through in vitro experimental measurements.

Influence of curing conditions on the interface bonding properties of CFRP plate–steel

To understand the influence of different curing conditions on the interface bonding performance of CFRP-reinforced steel plates, tensile tests were conducted on epoxy resin dog bone specimens and CFRP-reinforced steel plate double lap specimens. The study explored the tensile performance of dog bone specimens under different curing temperature/time conditions and the mechanical properties of double lap specimens under different curing pressures and curing temperature/time conditions. The results indicate that increasing the curing temperature can shorten the curing time of dog bone specimens and also improve their elastic modulus and tensile strength. Elevating the curing pressure, curing temperature, and extending the curing time cause a transition in the failure mode of the double lap specimens from surface fiber stripping of the CFRP plate to a mixed failure dominated by surface fiber stripping and adhesive–steel interface debonding, and the bearing capacity, interface ultimate slip, and peak shear stress of the specimens significantly increase, with the shear stress concentration zone gradually expanding from the loading end towards the free end, simultaneously, the ductility of the specimen increased, and the failure process was delayed. The ultimate load, interface peak shear stress, and ultimate slip of the specimens cured at 90 °C are significantly higher compared to the control group cured at 20 °C and 0.01 MPa. However, with increasing curing time, the rate of growth shows a decreasing trend.

Measurement of 3D joint surface morphology and estimation for shear mechanical behavior: A theoretical model and experimental investigation

The majority of rock engineering instabilities are primarily due to shear slips and failures on the joint surfaces, and the measurement of joint surface morphology is crucial for shear strength evaluation. In this study, the high-precision 3D laser scanner was first used to characterize and digitally reconstruct the surface morphology of various joints. The evaluation method of joint surface roughness was modified according to the 2D profile data and shear direction. Then, the effects of normal stress and initial joint roughness coefficient on the shear mechanical behavior were investigated by experimental method. The damage evolution characteristics and failure mechanism of the joint surface are analyzed by acoustic emission monitoring and image binarization calculations. The research results indicate that as the normal stress and initial joint roughness coefficient increase, the peak shear stress and shear displacement, residual strength, and cumulative AE counts of rock joints display an increasing trend. Based on the evolution of mechanical parameters, a new mechanical model of rock joints to predict shear strength and deformation was developed, which was validated by comparing the theoretical prediction curves with test results. A good concordance was achieved between the shear test and theoretical results, indicating that the developed model can effectively predict the shear strength and deformation of joint surfaces under different normal stress and roughness. This research results are expected to provide a valuable guidance for early warning and evaluation of geological disasters.

3D DEM investigation of shear behavior and interaction mechanism of woven geotextile-sand interfaces

This paper presents a numerical study on the investigation of microscopic mechanism governing the interaction of woven geotextile and angular sand employing the 3D discrete element method (DEM). The surface texture and tensile properties of the geotextile were simulated using overlapping spherical particles, and the angular sand was simulated using rigid blocks. The DEM models were fully calibrated based on previous experimental data. The shear and dilation zones of sand near the interface were quantitatively determined based on particle displacement gradients. Analysis of contact forces was conducted to explain the microscopic mechanism behind the macroscopic strength evolution. The influence of geotextile surface roughness on the shear strength of the geotextile-sand interface is also discussed. The results show that the failure mode of the woven geotextile-sand interface is a combination of particle sliding failure along the geotextile surface and shear failure of the sand within the shear zone above the interface. There is a rapid redistribution of contact forces prior to reaching peak shear resistance, and the average normal contact force within the shear zone remains relatively constant after the peak shear stress is achieved. A completely developed shear zone stabilizes soil deformation, typically after achieving the peak shear resistance.

Experimental and DEM analysis for the shear characteristics of interface between sand and irregular concrete under dynamic normal loading

To explore the dynamic shear property of sand–irregular concrete interface, a series of direct shear tests were conducted under dynamic normal loading. These tests were designed with various joint roughness coefficients (JRC), amplitudes and frequencies of dynamic normal loading. DEM models were established to analyze the microscopic mechanical behavior. The research results indicate that a larger amplitude and frequency of the dynamic normal loading would lead to a decrease in the interface shear stress and dilation. As the JRC increased, the interface shear strength first increased and then decreased, and the dilation increased. A rougher surface would reduce the phase shift between peak shear and normal stress. The phase shift between normal stress and friction coefficient was always half a normal loading cycle. A greater JRC would activate a more violent particle motion and a thicker shear band. The increase in effective roughness would lead to an increase in the deviation angle of the anisotropic direction. The evolution of force chains was observed in three-dimensional space. Weak force chains were screened out during the shearing process. As the shearing developed, the number of force chains decreased, the average length and strength of force chains continued to increase.

Study of the mechanical properties and propagation mechanisms of non-coplanar and discontinuous joints via numerical simulation experiments

Non-coplanar and discontinuously jointed rock masses are more complex than coplanar and discontinuously jointed rock masses. The mechanical properties and propagation mechanisms of non-coplanar and discontinuous joints were studied via direct shear tests with microscopic numerical simulation experiments. The numerical simulation tests were performed under different normal stresses, joint inclination angles, and shear rates. The numerical experimental results show that the microscale failure of non-coplanar and discontinuously jointed rock masses is mainly caused by tensile cracks. Additionally, when the peak shear stress is reached, the growth rate of cracks increases rapidly, and the number of cracks increases with increasing normal stress. The shear strength of non-coplanar and discontinuously jointed rock masses increases with increasing normal stress. Under the same normal stress, the variation curves of the shear strength of non-coplanar and discontinuously jointed rock masses with respect to the dip angle exhibit an “S”-shaped nonlinear pattern. Rock masses with joint inclination angles of approximately 15° and 65° have minimum and maximum shear strengths, respectively. The joint dip angle has a significant impact on the final failure mode of rock bridges in the rock mass. As the joint dip angle increases, the final failure modes of rock bridges change from “end-to-end” connection to a combination of “head-to-head” and “tail-to-tail” connections. The shear rate has a certain impact on the peak shear stress, but the impact is not significant. The spatial distribution of the tensile force chains changes as shearing progresses, and stress concentration occurs at the tips of the original joints, which is the reason for the development of long tensile cracks in the deeper parts.

Evaluation of cracking susceptibility of asphalt binders modified with recycled high-density polyethylene and polypropylene microplastics

The use of recycled plastics as modifiers for asphalt binder have gained attention in recent years. Studies have confirmed the enhancement in the rutting resistance of asphalt binder with the addition of these types of plastics, however there are controversies with regards to their long-term cracking performance. The long-term cracking performance of asphalt binder is directly influenced by their rheological properties. This study evaluated the fatigue performance of recycled High-Density Polyethylene (rHDPE) and recycled Polypropylene (rPP) modified asphalt binders using several rheological indices including the Superpave intermediate-temperature PG (G*sin δ), fatigue life (Nf), complex modulus (G*), phase angle (δ), the Glover-Rowe (G-R) parameter, the crossover temperature (Tδ=45°), the rheological index (R-value), the peak shear stress, failure strain and the yield energy, as well as a newly developed monotonic cracking index (MCI). Additionally, the influence of the process of mixing plastic with asphalt at high temperatures and shear rate on the cracking performance was also investigated. Results indicated that long term cracking performance were not consistent across all rheological indices. While Nf indicated improved overall cracking performance with the addition of rHDPE and rPP, G*sin δ, G-R parameter, R-value, Tδ=45°, and MCI indicated susceptibility to cracking with the addition of these recycled plastics.

Constraining Shear Strength of Fault Damage Zone Using Geodetic Data and Numerical Simulation

AbstractShear strength of damage zone, representing the stress threshold for rupture initiation, is a critical parameter in faulting mechanics. Despite its significance, the damage‐zone's shear strength has not been estimated in natural earthquake ruptures. Here we employed coseismic deformation and strain, kinematic slip model, and finite element modeling to determine the elastic properties and peak shear stress of coseismic damage zones along the 2021 Mw 7.4 Maduo earthquake. Through the analysis of the lowest shear stress resulting in surface ruptures and the highest stress without surface rupture, we constrained the strength within a range of 7–17 MPa. Our result is consistent with strength (5–16 MPa) of sandstone samples from laboratory tests, demonstrating the validity of this estimation. Although factors such as fault maturity and confining pressure influence strength variation, the strength can directly reflect the stress threshold required for macroscopic surface rupture formation in fault damage zones dominated by sandstone.

Primitive Chain Network Simulations for Double Peaks in Shear Stress under Fast Flows of Bidisperse Entangled Polymers.

A few experiments have reported that the time development of shear stress under fast-startup shear deformations exhibits double peaks before reaching a steady state for bimodal blends of entangled linear polymers under specific conditions. To understand this phenomenon, multi-chain slip-link simulations, based on the primitive chain network model, were conducted on the literature data of a bimodal polystyrene solution. Owing to reasonable agreement between their data and our simulation results, the stress was decomposed into contributions from long- and short-chain components and decoupled into segment number, stretch, and orientation. The analysis revealed that the first and second peaks correspond to the short-chain orientation and the long-chain stretch, respectively. The results also implied that the peak positions are not affected by the mixing of short and long chains, although the intensity of the second peak depends on mixing conditions in a complicated manner.

Effects of freeze-thaw cycles on the tensile properties of geogrids and shear behavior of geogrid-soil interface

The tensile strength of geogrids and the shear strength of the reinforced soil interface are critical technical indicators for designing reinforced soil structures. This study developed a temperature-controlled apparatus to examine the tensile properties of geogrids subjected to freeze-thaw cycles within the soil, and the effect of interface temperature and freeze-thaw cycles on the shear behavior of the geogrid-soil interface. Eight and four groups of direct shear and tensile tests were conducted on the geogrid-soil interface and geogrids, respectively, under varying conditions. The peak tensile strength of geogrids remained similar to that of non-freeze-thaw samples after experiencing freeze–thaw cycles within the soil. tensile properties of geogrids were independent of the number of freeze–thaw cycles. At constant water content (w=6%), the peak shear stress at the geogrid-soil interface decreased by 24% (7 freeze-thaw cycles) compared to the non-freeze-thaw group. The cohesion and friction angle of the geogrid-soil interface decreased with increasing freeze-thaw cycles but tended to stabilize after 4 freeze-thaw cycles. The reinforcement provided by the geogrid enhanced with decrease in the interface temperature. The shear stress was higher at interface temperature under 0 °C, whereas in a non-frozen state, the interface exhibited lower shear stress with a consistent stable value.

Influence of elevated temperatures on the bond performance of CFRP-steel lap joints bonded by nanosilica-modified adhesive with mixed curing agents

Elevated temperatures may influence greatly the mechanical properties of adhesives, and it is difficult for adhesives with a single curing agent to meet the requirements of adequate heat resistance and toughness simultaneously. First, this paper proposes a nano-SiO2-modified epoxy adhesive (GY34) using mixed curing agents to improve the bond performance of CFRP-steel joints at a high temperature. Then, studies are taken to examine the impact of elevated temperatures on the mechanical performance of GY34 with mixed curing agents and the interfacial properties of CFRP-steel double-lap joints bonded by GY34. After that, models are developed to predict the bearing capacity and bond-slip of CFRP-steel double-lap joints at different temperatures using the test data. The results indicate the toughness is optimal at 70 °C when the curing agents C105 and D230 are mixed with a mass ratio of 1:2. The bearing capacity of the CFRP-steel lap joint bonded with GY34 is much higher than the cases only bonded with a single C105 or D230, respectively. Moreover, the load-displacement curve has a significant ductile development stage as the temperature rises below the glass transition temperature (Tg, S), beyond which, the bearing capacity declines. In addition, the length of shear stress transmission and the effective bonding length increase significantly at high temperatures. The bond-slip curve bonded with GY34 has a trilinear trapezoid shape at different temperatures, and the peak shear stress and stiffness decline at various elevated temperatures. Finally, the relative slip and interfacial fracture energies increase first and then decrease with the rise of temperature.

Cyclic shear behavior and BoBiLSTM-based model for soil-rock mixture-concrete interfaces

In order to study the impact of surface roughness on the cyclic shear characteristics of the Soil-Rock Mixture and concrete interface, a series of cyclic shear tests were conducted using a large indoor direct shear apparatus. The effects of three concrete surface roughness coefficients JRC (0.4, 9.5, 16.7), five rock content levels (0%, 25%, 50%, 75%, 100%), and three cyclic shear displacement amplitudes (1, 3, 6 mm) on interface cyclic shear stress and Soil-Rock Mixture shear deformation were analyzed. A Bidirectional Long Short-Term Memory (BoBiLSTM) model was proposed, utilizing Bayesian optimization and k-fold cross-validation for hyperparameter tuning to streamline the model parameter selection process and enhance the prediction accuracy of the stress-strain relationship under cyclic loading. The experimental results show that, under five rock content levels, as the concrete surface roughness coefficient and cyclic shear displacement amplitude increase, the interface average peak shear stress increases accordingly. The interface average peak shear stress of the sample with 75% rock content is the highest; in terms of vertical displacement, the sample with 50% rock content has the maximum displacement, while the sample with 25% rock content has the minimum. The two types of samples show different soil deformation patterns in the two shear directions during the cyclic shearing process; as the shear displacement amplitude increases from 1 mm to 3 mm and 6 mm, the greater the concrete surface roughness, the smaller the change in shear stiffness and damping ratio. Compared to traditional Long Short-Term Memory (LSTM) models, the BoBiLSTM model demonstrated improvements in the average metrics of R2, RMSE, and MAPE by 0.32%, 57.25%, and 72.32%, respectively.