Numerical Study on the Influence of Fault Structure on the Geostress Field

Abstract

A geostress field continuously evolves with long-term tectonic activity. A fault, as a general product of tectonic movements, has a great influence on the geostress field in the vicinity. To analyze the geostress field characteristics and influencing factors near the fault fracture zone in high-altitude areas, this study takes the Dianda-Piru fault on the Qinghai–Tibet Plateau as its research object. Based on the geological conditions and in situ stress measurement data in the study area, a refined numerical model was established using numerical simulation to invert the geostress field in the vicinity of the fault fracture zone, and a quantitative analysis of the factors influencing the geostress distribution was carried out. The results show that the overall relationship between large horizontal principal stress σ_H, vertical stress σ_v, and small horizontal principal stress σ_h is σ_H > σ_v > σ_h, and the surrounding rock stress is dominated by horizontal stress. Geostress is released within the fault fracture zone to a certain extent, and there is a certain degree of stress concentration within the intact rock mass on the upper plate of the fault. The elastic modulus has a greater influence on the geostress field near the fracture structure area than Poisson’s ratio, and the range of the stress-weakening zone increases with the decrease in the elastic modulus. The maximum principal stress inside the fault increases with the increase in the angle between the fault strike and regional principal stress, while the deflection angle of the surrounding principal stress direction decreases with the increase in this angle. The study of the distribution law of geostress fields with developed fracture structures can provide theoretical guidance for the sustainable development of engineering construction in tectonically active areas.

1. Introduction

Geostress is an important element of the basic data used for geological environment and crustal stability evaluation, geological engineering design, and construction. The study of the spatial distribution state of geostress under fault disturbances is a key step in underground structure stability analysis, as well as the prediction of rock bursts and large deformations in resource exploitation [1,2,3]. Due to the superposition of diagenesis and geological structure movement disturbance, the geostress characteristics within a fault and its influence zone are very complex [4,5]. The analysis and research of geostress characteristics in fault zones have attracted growing attention from geologists and geotechnical engineers.

The results of a large number of in situ stress measurements [6,7,8,9] indicate that fracture structures, regardless of their size, can have a certain impact on the stress state in their vicinity, and this influence is highly complex. In recent years, through methods such as multiple regression, numerical simulation, and experimental research, many scholars have observed and confirmed that fracture structures have a significant influence on the stress state, direction, and magnitude of the Earth’s crust [10,11,12]. Complex fracture systems, bedding, folds, joints, and other geological discontinuities have a significant impact on the stress state, leading to variations in the magnitude and direction of stress [13,14,15]. For example, fault systems can control the deformation of rock masses and affect the deformation response of underground excavations in soft rock [16]. Each fracture’s structure, the magnitude of tectonic stress, and the proximity to fractures play a crucial role in disturbing the regional stress field and forming small-scale variations [17]. The stress state of the Earth’s crust is related to the dynamic nature of faults [18], and different fault factors such as the fault activity distance, slip rate, friction coefficient, fault thickness, and fault dip angle significantly influence the distribution of the stress field [19]. The growth of stress and the displacement of rock masses near faults can reflect the activation characteristics of fault structures [20]. After the 2008 Wenchuan earthquake, hydraulic fracturing tests were conducted to measure the in situ stress of active faults, revealing the fundamental principle that the stress field near the fault is primarily controlled by horizontal principal stress [21]. The stress direction near the fault differs significantly from the regional tectonic stress and is accompanied by clear fault activity effects [22].

This study takes the Dianda-Piru fault on the Qinghai–Tibet Plateau as its research object. Based on the collection of regional measured geostress data and in situ investigative work, we used the multiphysics finite element numerical simulation software COMSOL Multiphysics 6.0 to a establish a three-dimensional model containing the fault structures of the study area and study the influences of fault structures on the geostress field in the region. This research can provide a reliable scientific basis for assessing the geological environment, crustal stability, and the prevention and control of geological hazards in high-stress areas associated with fault structure development.

2. Geological Background

The division and regional tectonic geological characteristics of the tectonic units on the eastern margin of the Qinghai–Tibet Plateau are closely related to its tectonic evolution. As a unique natural regional unit on Earth, the strong uplift of the Qinghai–Tibet Plateau (beginning in the Late Cenozoic) and its impact on the climate and environment of its surrounding areas have been a concern for the scientific community. It is a hotspot and key area for international research on Earth sciences and resources and environmental science. The study area is located in the middle of the Hengduan Mountains, in the hinterland of the “Three Rivers” tectonic belt. It is an extension of the Tanggula Mountains of the Qinghai–Tibet Plateau and turns to form a boundary between the Songpan–Ganzi active continental margin belt and the Chang du continental block first-order tectonic units.

The study area is covered by Quaternary fluvial and alluvial deposits. The bedrock primarily consists of Triassic sandstone interbedded with shale, limestone, and mudstone, as well as sandstone and conglomerates interlayered with mudstone. Additionally, there are areas of basalt, andesite, granite, and diorite. The main faults developed in this area are the Dian da-Piru fault, Eyi fault, and other major fractures. The fault distribution in the study area is shown in Figure 1. The main regional faults can be described as follows:

Dianda-Piru fault: This fault is situated in the western part of the Niangxi-Gepo magmatic arc volcanic belt. It runs north-northwestward and forms an eastward convex arc on the map. The fault is truncated by the F25 detachment fault at its southern end and extends into the neighboring area to the north. The fault length in this area is 105 km. The fault plane dips to the west at an angle of 50–65°. The width of the fault zone is approximately 100 m. The fault developed in the Upper Triassic Jinggu Formation and Waqu Formation, and it cuts off the overlying Bula Formation and Bolila Formation. In the northern section of the fault, it cuts off the Lower Tertiary Gongjue Formation, and in the southern section it exposes the Middle Triassic Walasi Formation.

Eyi Fault: This fault was examined through satellite interpretation in this study. It is distributed in a north-northwest direction, with a small scale. The lithology of the upper and lower plates of the fault zone is the same. The shallow layer is mainly brownish-red silty mudstone, with a layered structure of medium thickness, mainly formed of clay minerals. The deep layer is mainly sandstone interbedded with conglomerates. The dip angle of the surrounding rock strata is approximately 40~50°.

3. Methods

3.1. Establishment of the Three-Dimensional Fault Model

The area selected for this study is a rectangular region near the Dianda-Piru fault, measuring 2000 m × 1000 m (Figure 2). Considering the fault zone and its influence area, we set up a thin-layer fault structure with a width of 100 m, which cut through the strata and extended to the surface, and we assigned materials according to the fault-related attributes. After importing the model into the COMSOL calculation software, grids were generated. The complete grid of the calculation model contained 1,476,314 tetrahedral elements, 38,660 triangular elements, 921 edge elements, and 16 vertex elements. The rock mass was defined as a Mohr–Coulomb constitutive model.

3.2. Boundary Conditions

According to the structural dynamic background and related regional literature data [23,24] for the study area, displacement constraints of the UX and UY directions were loaded on the west and south boundaries—that is, surface displacement loads intersecting with the boundary at a certain angle. In the calculation process, a boundary load adjustment method was adopted with reference to the measured ground stress data for the inversion calculation. The best boundary loading mode and combination mode were finally determined, as illustrated in Figure 3. Uniform loads of 20 MPa and 15 MPa were applied to the corresponding boundaries of the X and Y directions of the model, respectively.

3.3. Physical and Mechanical Parameters of Rock Mass

In the three-dimensional structural geostress field’s linear elastic finite element numerical simulation, parameters such as the elastic modulus E, Poisson’s ratio ν, and the rock density of the material medium needed to be determined. According to the borehole-measured lithology parameters and the indoor test results of the rock samples near the surface of the work site, the variation law of the rock mechanics parameters with the depth of the borehole points in the study area was analyzed. After firstly determining the parameters, they were input into the model for calculation. By comparing the calculated stress values for the boreholes with the measured stress values for the boreholes, a further inversion correction of the rock mechanics parameter assignment was carried out. Through repeated correction and verification, we finally determined the physical and mechanical parameters of the rock mass for this study. The specific parameter values are shown in

Table 1. Model rock parameter values.

Lithology	Stratigraphic Code	Modulus of Elasticity (GPa)	Poisson’s Ratio	Density (kg/m3)
Siltstone, lithic sandstone	E2r3	20	0.33	2130
Argillaceous siltstone, lithic sandstone	T3a	18	0.35	2300
Lithic sandstone, conglomerate	T3j	22	0.26	2320
Brecciform limestone	T3b	30	0.25	2400
Lithic sandstone	T3d	20	0.35	2300
Andesite, basalt	T3dk	45	0.23	2400
Limestone, breccia, siltstone	T3g	35	0.26	2420
Conglomerate, sandy conglomerate	T3dd	25	0.28	2230
Gneiss, quartz schist	Pt1–2Nd	35	0.25	2300
Diorite porphyrite	γδT3	50	0.2	2420
Granodiorite	ηγT3	50	0.21	2420
Fault fracture zone	/	6	0.32	2550

.

3.4. Characteristics of the Geostress Field in the Study Area

To obtain effective in situ stress measurement data, the hydraulic fracturing method recommended by the International Society for Rock Mechanics [25,26,27] was used to measure the in situ stress at 21 points with different depths in 5 boreholes (named G1, G2, G3, G4, and G5, respectively) in the study area. The measurement points were buried at depths ranging from 182 to 700 m. The characteristics of the rock strata of the borehole points mainly consisted of calcareous sandstone, gray–black shale, sandstone, mudstone, and sandy mudstone.

To better analyze the orientation of the in situ stress within the region, we incorporated measured data from 13 borehole locations on the sites of five surrounding engineering projects to optimize the statistical results. The maximum horizontal principal stress direction was converted into the azimuth angle for statistics. The specific statistical results are shown in Figure 4.

The maximum horizontal principal stress direction in the region was mainly northeast and northwest (Figure 4). There were 8 measured values with an azimuth angle of northwest, with an average angle of 309.37°, accounting for a small proportion of the data and representing a local stress state. The data pointing in the northeast direction had 23 values, with an average azimuth angle of 42.33°, being relatively normally distributed. Many scholars have analyzed a large number of earthquake focal mechanism solutions in the Qinghai–Tibet Plateau [28,29] and pointed out that the principal compressive stress axis orientation of most earthquake focal mechanism solutions is arranged in the northeast–southwest direction, concentrated in the range of 0~50°, with a dominant orientation of 20~40°. The maximum horizontal principal stress direction in the study area is mainly northeast–north-northeast, and the principal stress direction has a clockwise deflection near the east tectonic junction. It also shows a trend from south to north as north-northeast→northeast, which is nearly perpendicular or large-angle intersecting with the northwest-west-trending faults and nearly parallel or small-angle intersecting with the northeast-trending faults. The stress direction distribution characteristics in the study area are similar to those of GPS vectors.

The distribution characteristics of principal stress values with depth are shown in Figure 5. The range of maximum horizontal principal stress near the measuring point was 5.71~24.6 MPa, the range of minimum horizontal principal stress was 4.79~16.36 MPa, and the range of vertical principal stress was 4.86~17.99 MPa. The dominant orientation of the maximum horizontal principal stress was northeast according to the statistical results, and the azimuth angle was calculated as N42.33°E, which is consistent with the tectonic stress field data in this area. The relationship between the three principal stress values in the study area conformed to σ_H > σ_v > σ_h, and the stress structure was mainly the strike-slip type. The maximum horizontal principal stress was the main factor affecting the geostress field distribution.

4. Results and Discussion

4.1. Comprehensive Reliability Evaluation

According to the data collection and analysis of the regional stress directions, it was found that the main direction of maximum principal stress in the study area was mainly in the south–north and northeast directions, with a dominant orientation of approximately 20~40°. The maximum principal stress direction of this area was 42.33° according to the statistical data of the measured boreholes in the study area. We obtained the principal stress vectors at different depths through model calculations and found that the direction of the maximum horizontal principal stress in the region ranges from 20° to 60°. The main stress in the axis area was less affected by the boundary conditions, and the main stress direction range was corrected to 20~45°—that is, the north-northeast–northeast direction, which is consistent with the northeast direction of regional tectonic plate squeezing movement and with the main stress direction obtained using previous methods, such as focal mechanism solution analysis.

By comparing the simulation results with the measured ground stress of the boreholes, the reliability of the numerical inversion results was verified. The results are shown in Figure 6. Generally speaking, the statistical results of the measured ground stress values and the calculated values are within the ideal range of error, and the variation laws are essentially consistent. They all conform to the regional stress distribution law of σ_H > σ_v > σ_h. It can be considered that the geostress field distribution law obtained by using the three-dimensional model calculation in this study is close to the actual situation, and the simulation result is relatively reliable.

4.2. Analysis of Geostress Field Inversion in the Fault Region

After completing the calculation of the model with the parameter settings, we proceeded to cut out a section from the central axis position of the study area. We set the display form of the principal stress on the section to the equal stress line form and obtained the cloud map of the maximum horizontal principal stress, minimum horizontal principal stress, and vertical principal stress in the central axis position. The specific stress distribution can be seen in Figure 7.

The stress values in the vicinity of a fault are significantly lower than those in the adjacent regions of undisturbed rock, due to stress release resulting from fault evolution and activity, as well as the weakening of the physical mechanical properties of the rock mass near the fault. As one moves away from the fault zone, this influence gradually diminishes. Near a fault, rocks typically undergo fracturing and displacement, leading to the accumulation and release of stress, thereby causing a pronounced stress concentration at the fault’s terminus.

As can be seen from Figure 7, the maximum horizontal principal stress, vertical principal stress, and minimum principal stress all change significantly near the fault. The stress in the fault’s center position is significantly lower than that on the two sides of the fault, and the stress value gradually increases as the observation point moves away from the fault. Some stress release phenomena occur near the middle section of the fault, while there is some stress concentration at both ends of the fault.

4.2.1. Distribution of Vertical Principal Stress

The physical and mechanical properties of the rock are among the most important factors affecting the vertical principal stresses. The vertical principal stress in the fault area of this model is significantly weakened compared with other areas. As shown by the stress contour lines in Figure 7, a more obvious stress concentration phenomenon occurs on the right side of the fault, and the stress changes sharply at the boundary between the hanging wall and the footwall, while a stress-weakening zone with a significant stress value drop is formed inside the fault. As shown in Figure 7c, the vertical stress values increase significantly from the fault center to the fault boundary. Specifically, from the fracture center to the left fault boundary, the vertical stress value increases by 4.67 MPa, while from the fracture center to the right fault boundary, the vertical stress value increases by 4.8 MPa. After passing through the boundary, due to the gradual recovery of the rock’s physical and mechanical strength with the diminishing influence of the fault zone, the vertical stress value also gradually increases by approximately 1.2~1.4 MPa within a 500 m range. The specific change rule of the axis stress value is shown in curve A in Figure 8.

4.2.2. Distribution of Maximum Horizontal Principal Stress

Affected by the stress release phenomenon caused by fault evolution and activity and the weakening of the rock’s physical and mechanical properties, the stress value in the fault area is significantly lower than that in the nearby ordinary rock strata, where the maximum horizontal principal stress range is 9.58~12.96 MPa. The stress value on the right side of the fault (hanging plate) changes relatively smoothly, and the axis stress changes from 13.96 to 14.51 MPa from the fault edge to the area where the stress changes gradually. On the left side of the fault (foot plate), the stress value changes more sharply as the distance from the fault boundary gradually increases. Within 350 m from the boundary, the value is lower than that in the symmetrical position on the hanging wall. After exceeding 350 m, it continues to rise beyond that in the symmetrical position on the hanging wall. The stress value changes from 12.62 to 15.25 MPa with progressive distance from the fault boundary. The change rule of the stress value in the axis area can be seen in curve B in Figure 8.

4.2.3. Distribution of Minimum Horizontal Principal Stress

As can be observed from the contour image in Figure 7, a clear stress concentration phenomenon appears on the right side of the fault in the minimum horizontal principal stress image. The stress value decreases gradually as the observation point moves away from the fault boundary and forms a strip-like stress-weakening zone on the right side. After passing through the stress-weakening zone, the stress value gradually increases. The minimum horizontal principal stress on the right side of the fault changes from 4.43 MPa to 7.71 MPa in the process of moving away from the boundary by 500 m and decreases by 3.28 MPa from near to far. On the left side of the fault, however, the distribution rule of minimum horizontal principal stress is completely different, with no clear stress concentration or release phenomenon, only gradually increasing in the process of moving away from the fault boundary, from 4.33 MPa to 6.95 MPa, with a total increase of 2.62 MPa. The variation law of the stress value in the axial region is shown in curve C in Figure 8.

4.3. Influence of Mechanical Parameters on Fault Stress

4.3.1. Influence of the Rock’s Elastic Modulus on Fault Stress

While maintaining a constant Poisson’s ratio and boundary conditions for the fault rock, we altered the elastic modulus of the fault fracture zone. Subsequently, we analyzed the variations in the geostress field near the fault under different elastic modulus ratios between the fault rock and the surrounding normal rock, specifically, 1/35, 2/7, 4/7, and 1. As shown in Figure 9, the stress of rock on both sides of the fault increases with the increase in the elastic modulus value, but this increase is not great. Generally speaking, when the elastic modulus of fractured structural rock increases gradually to the size of the surrounding normal rock’s elastic modulus, the maximum horizontal principal stress in the axis position on both sides of the fault increases by approximately 8.3 MPa. The maximum horizontal principal stress of the fractured structure itself in the axis position shows a more apparent increase, and its increase reaches nearly 9 MPa with the increase in the elastic modulus. Its maximum horizontal principal stress increases by nearly 3 MPa for every 10 GPa increase in the elastic modulus.

The stress concentration phenomenon at the ends of the fault becomes more apparent in the geostress field distribution when the elastic modulus is low. As the elastic modulus gradually approaches the average level of the rock on both sides, the stress concentration area gradually decreases until it disappears. This suggests that as the strength and hardness of fractured structural rocks decrease, the weakening effect of the stress on the surrounding area becomes stronger, leading to the formation of a larger stress-weakening zone. When the elastic modulus value of the fault rock reaches the same level as that of the surrounding rock, it indicates that the internal stress value of the fault structure at this time even exceeds the surrounding stress by approximately 2 MPa due to the discrete structure and uneven stress distribution within the fault fracture zone.

When studying the influence of the fault’s elastic modulus on the regional geostress field direction, it can be seen that when the fault’s elastic modulus is in the range of 10~35 GPa, the different elastic modulus values have a great influence on the geostress field direction around the fault. When the elastic modulus value is low, the stress direction near the fractured structure shows severe deflection, and the ground stress in rock on both sides of the fault is deflected nearly 90° from the initial maximum principal stress direction (Figure 10a). As the elastic modulus increases, the deflection size and range of the maximum principal stress on both sides of the fault decrease accordingly. When the elastic modulus value approaches the strength value of the surrounding rock, the influence range weakens near both ends of the fault, and the deflection angle decreases to approximately 45°. At the same time, the maximum principal stress direction at the boundary of the lower plate of the fault is almost vertical, but the influence range is only approximately 50 m outward from the boundary due to the influence of the fault’s discontinuous surface and rock anisotropy. Studying the variation patterns of the in situ stress magnitude and direction near fault zones under different elastic modulus values in the fractured fault zone helps in assessing the deformation capability and stress concentration conditions of the fault. Consequently, it enables the prediction of the fault’s slip and rupture potential, providing important references for rock mechanics and fault studies.

4.3.2. Influence of the Poisson’s Ratio of the Rock on Fault Stress

The fault rock’s elastic modulus and boundary conditions were fixed, and Poisson’s ratio was taken to be 0.15, 0.2, 0.25, 0.3, and 0.35, to observe the regional geostress field distribution. When Poisson’s ratio takes different values within the reasonable range, the regional maximum principal stress changes very little. The contour area cloud map cannot clearly show the stress value changes under each working condition. Therefore, the black and white contour form is used to show the regional stress distribution characteristics in Figure 11. The overall rule of regional stress is that the maximum principal stress decreases with the increase in Poisson’s ratio. Additionally, it can be observed that with the increase in Poisson’s ratio, a stress release area gradually forms in the middle area on the right side of the fault. The area of the stress release area increases with the increase in Poisson’s ratio, and the stress value of the release area decreases accordingly.

Poisson’s ratio determines the non-uniformity of stress distribution and the degree of stress concentration. By studying the Poisson’s ratio of rocks, one can gain insights into the stress distribution near fault zones, including the magnitude and direction of stresses. This, in turn, reveals the regions of stress concentration and the mechanisms of stress transfer within the fault. Researching the Poisson’s ratio of rocks provides essential foundations for assessing fault activity and predicting seismic risks.

4.3.3. Influence of the Maximum Principal Stress Direction on Fault Stress

Under the condition that the boundary load was unchanged, we adjusted the direction of the fault in the model to meet the change in the angle between the regional maximum principal stress and the fault. We analyzed the geostress field distribution characteristics under conditions where the angle between the regional maximum principal stress direction and the fault trend was 0°, 30°, 45°, 60°, and 90°. The layout of each working condition is shown in Figure 12 below.

By calculating the regional maximum principal stress contour lines under each working condition (Figure 13), it can be seen that if the angle between the regional maximum principal stress direction and the fault changes, the maximum principal stress distribution characteristics also exhibit clear changes. With the increase in angle α, the maximum principal stress boundary gradually reduces the influence of stress on the fault end. If the fracture direction gradually rotates to be perpendicular to the maximum principal stress direction, the end is almost unaffected by the maximum stress boundary, and at this time, the area of stress concentration also rapidly shrinks.

In the process of the gradual change in the angle between the fracture structure and the maximum stress boundary, the position and shape of the stress release area are constantly changing throughout the whole model area but are always located in the fault’s lower plate area. The overall value of the regional maximum principal stress does not change significantly under each working condition, but the internal stress change trend of the fault structure is clear, and the larger the angle between the regional maximum principal stress direction and the fault, the greater the structural stress inside the fault will be. When α = 0°, the maximum principal stress value in the fault’s middle section is 10.03 MPa, and with the increase in the angle, its value increases to 19.43 MPa, with a difference of nearly 10 MPa. In close proximity to the fault boundary, the maximum principal stress value of the fault’s lower plate is significantly higher than that of the upper plate, and the difference range is approximately 0.5~3 MPa. With the increase in the angle between the fracture structure trend and the regional maximum principal stress direction, the difference in the maximum principal stress between the fault’s two plates becomes larger. This phenomenon is due to the fact that the fault’s lower plate area will not only produce a stress release area within a certain distance range but also produce a stress concentration belt near the fault boundary. After further increasing the distance and leaving the range of the stress release area, the lower plate’s maximum principal stress will gradually rise to the regional average stress level.

The fracture structure not only affects the size of the nearby principal stress values but also disturbs the direction of the maximum principal stress near the fracture. As can be seen from Figure 14, the direction of the maximum principal stress has the tendency to turn perpendicular to the fracture structure under each working condition, so the difference in the rotation angle under different conditions is significant. In this study, the counterclockwise rotation of the angle of regional principal stress is defined as positive. Under the α = 0° condition, the principal stress deflection angle near the fracture structure reaches 60~90°, and the rotation is mostly concentrated on the upper plate, while for the lower plate it is relatively minimal. Under the α = 45° condition, the change in the stress direction in the surrounding area is most apparent due to the strong influence of shear stress on the fault zone. The main part of the fault has a maximum principal stress deflection of approximately −15~−45°, and the area near the fault also produces a deflection angle of approximately 10°, which is opposite to the fault deflection direction, mainly for the fault’s upper plate area. Under the 90° angle condition, the direction of the maximum principal stress does not change significantly. It can be seen that the larger the angle between the fracture structure and the regional maximum principal stress direction, the more apparent the principal stress deflection occurring inside the fault will be.

5. Conclusions

Understanding the influence of a fault on the adjacent geostress field is helpful for explicating geological problems related to underground engineering. Based on field investigations and data collection, the characteristics of the geostress field in the study area were analyzed using a focal mechanism solution and statistical analysis. Considering the mechanical parameters of a fault, their influences on the geostress field were analyzed through a numerical simulation. The following conclusions were reached:

• In the study area, the measured direction of the principal stress is approximately northeast, with an average bearing of 42.33°. The overall relationship between the three principal stress values is influenced by strong horizontal tectonic stresses and can be expressed as σ_H > σ_v > σ_h. Among the various stresses in the adjacent regions, the maximum horizontal principal stress is the primary factor influencing the distribution of the stress field.
• The changes in the principal stresses near the fault are clear, and the general trend is that the principal stress values in the fault fracture zone are low. With increasing distance from the fault fracture zone, the stress magnitude gradually increases and reaches the level of the stress values in the surrounding area. The stress change laws of the two plates of the fault are different. In the upper plate, the stress concentration area and stress release area generally coexist, and most of the stress concentration areas are close to the fault boundary, while there is a certain distance between the stress release area and the fault.
• Among the four variables of the rock elastic modulus E, Poisson’s ratio ν, boundary stress direction, and fault strike angle α, the elastic modulus E and angle α have the most pronounced impacts on the stress distribution along the fault. As the elastic modulus increases, the deviation angle of the principal stress directions on both sides of the fault decreases. The region of stress concentration near the fault decreases with increasing α, while the main characteristic of the stress release zone is its constant location beneath the fault, with relatively minor differences in relation to variations in α.