scholarly journals A New Calculation Method for the Soil Slope Safety Factor

2017 ◽  
Vol 2017 ◽  
pp. 1-6
Author(s):  
Fu Zhu ◽  
Wanxi Zhang ◽  
Mingzhi Sun
Keyword(s):  
Stress State ◽  
Principal Stress ◽  
Safety Factor ◽  
Lateral Pressure ◽  
Pressure Coefficient ◽  
Intermediate Principal Stress ◽  
New Method ◽  
Soil Slope ◽  
Lateral Pressure Coefficient ◽  
Slope Safety

Based on the unified strength theory, a new method to calculate the plane soil slope safety factor was derived that considers the effect of intermediate principal stressσ2and at-rest lateral pressure coefficientK0. Calculation examples from the literature were used to compare the new calculation method and the current slice method; the results showed that both provided good consistency. The new method can provide a reference for slope stability evaluation. The new method was used to calculate the soil slope safety factors for different values of intermediate principal stress parameterb, double shear stress parametersuτ′, and static lateral pressure coefficientK0. The results showed that the safety factorFsincreased whenbwas increased;Fsfirst increased and then decreased whenuτ′was increased; andFsincreased whenK0was increased. These results show that the intermediate principal stress as well as the stress state and its changes cannot be ignored during soil slope stability analysis. The slope soil characteristics and stress state should be considered to determine the unified strength theoretical parameters and static lateral pressure coefficient, maximize the potential of slope soil strength, and effectively reduce the costs of soil slope engineering.

scholarly journals Analysis of plastic zones in surrounding rocks around a circular tunnel considering the effect of intermediate principal stress and heterogeneity

2019 ◽  
Vol 275 ◽  
pp. 03007 ◽  
Author(s):  
Shuxin Deng ◽  
Yonglai Zheng ◽  
Lipo Feng ◽  
Le Van Tuan ◽  
Cuizhou Yue ◽  
...  
Keyword(s):  
Plastic Zone ◽  
Principal Stress ◽  
Lateral Pressure ◽  
Pressure Coefficient ◽  
Plastic Zone Size ◽  
Intermediate Principal Stress ◽  
Circular Tunnel ◽  
Lateral Pressure Coefficient ◽  
Calculation Results ◽  
Coulomb Criterion

Based on a modified Mohr-Coulomb criterion with a non-uniform coefficient, a calculation method of plastic zone boundary of surrounding rocks in a circular tunnel in non-uniform stress field is established. Both the effects of intermediate principal stress and heterogeneity are studied. With the increase of the intermediate principal stress, the plastic zone size of the surrounding rocks will decrease first and then increase. Lateral pressure coefficient has an effect on the shape of the plastic zone. With the increase of lateral pressure coefficient, the plastic zone gradually becomes uniform, and the failure of surrounding rock develops upward and downward from both sides. As non-uniform coefficient increases, the material is more uniform and the effect of intermediate principal stress on the plastic zone is less significant. If the effect of intermediate principal stress is not taken into account, the calculation results tend to be consistent with results calculated by the Mohr-Coulomb criterion, which are considered to be conservative.

Analysis of Three-Dimensional Excavation Slope Stability Subjected to In Situ Stress Based on Strength Reduction FEM

2011 ◽  
Vol 374-377 ◽  
pp. 2157-2162
Author(s):  
Jun Qi Wang
Keyword(s):  
Slope Stability ◽  
Safety Factor ◽  
Lateral Pressure ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Horizontal Stress ◽  
Strength Reduction ◽  
Lateral Pressure Coefficient ◽  
Slope Direction

Slope usually lies in an initial stress field, especially in complex three-dimensional stress conditions. When horizontal stress is larger than vertical stress or the two horizontal stresses are not the same, the horizontal in-situ stress has significant effect on the excavation slope stability. To investigate the effects of the original in-situ stresses, the strength reduction method is used to analyze three-dimensional excavation slope, and Mohr-Coulomb yield rule is adopted, the failure criterion based on analysis convergence is suggested. First, the horizontal stress is uniform based on the gravity load, when lateral pressure coefficient increases, the safety factor decreases, and the plastic zones develop from slope to foot foundation. Then the condition of lateral pressure coefficient change is analyzed, slope direction pressure coefficient increases, plastic zone on the slope bottom increases, the safety factor decreases remarkably. Using the same method to analyze that of the lateral pressure coefficient on the slope face direction increases, the slope FS increases little holding the K2 unchanged with the K1 adding. The results show that the slope direction pressure coefficient has more effects on the safety coefficient than that of the axis.

scholarly journals Failure Characteristics and Stability Control of Roadway Surrounding Rocks under Different Lateral Pressure Coefficients

2020 ◽  
Vol 13 (5) ◽  
pp. 42-49
Author(s):  
Zhiyu Chen ◽  
◽  
Zhiqiang Yin ◽  
Jucai Chang ◽  
Wenbao Shi ◽  
...  
Keyword(s):  
Principal Stress ◽  
Lateral Pressure ◽  
Pressure Coefficient ◽  
Maximum Principal Stress ◽  
Stability Control ◽  
Simulation Software ◽  
Particle Flow Code ◽  
Lateral Pressure Coefficient ◽  
Working Face ◽  
The Stability

The stability control of mining roadways is crucial in ensuring the safe and efficient mining of deep coal resources. Given the effect of mining stress on the working face, the support scheme of such roadways, which is designed based on the original in-situ stress parameters, often presents support-related problems. A mining roadway on the 1131 working face of Zhujidong Coal Mine in the Huainan mining area, China was taken as the engineering background of this study. To explore the influence of mining stress on the stability control of this roadway, the 2-dimensional (2D) Particle Flow Code (PFC) numerical simulation software was used to perform a simulation study on the stress distribution characteristics and deformation failure laws of the surrounding rocks under the change in the roadway lateral pressure coefficient caused by the mining stress. An improved support scheme that considers the influence of varying lateral pressure coefficient on the mining roadway was then proposed. Results show that when the lateral pressure coefficient increased from 1 to 1.4, the maximum principal stress (61.2 MPa) is observed at 2.9 m inside the roof of the surrounding rocks in the roadway. When the lateral pressure coefficient decreases from 1 to 0.4, the maximum principal stress (46.2 MPa) is observed at 2.2 m inside the surrounding rock of sidewalls of the roadway, and failure occurs. These findings suggest that the deformation and failure of surrounding rocks are affected regardless of the lateral pressure coefficient increase or decrease. On this basis, the lengths of the anchor bolts in the roof and sidewalls in the original support method are increased from 2,200 mm to 3,000 mm and 2,500 mm, respectively. The field monitoring results indicate that the improved support method mitigates the deformation and realizes the stability control of the roadway surrounding rocks. The findings of this study could provide a scientific basis for the parameter design of roadway support.

scholarly journals Numerical Study on Damage Zones Induced by Excavation and Ventilation in a High-Temperature Tunnel at Depth

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4773
Author(s):  
Jianyu Li ◽  
Hong Li ◽  
Zheming Zhu ◽  
Ye Tao ◽  
Chun’an Tang
Keyword(s):  
High Temperature ◽  
Lateral Pressure ◽  
Numerical Study ◽  
Pressure Coefficient ◽  
Fracture Morphology ◽  
In Situ Stress ◽  
Surrounding Rock ◽  
Geothermal System ◽  
Mechanical Coupling ◽  
Lateral Pressure Coefficient

Geothermal power is being regarded as depending on techniques derived from hydrocarbon production in worldwide current strategy. However, it has artificially been developed far less than its natural potentials due to technical restrictions. This paper introduces the Enhanced Geothermal System based on Excavation (EGS-E), which is an innovative scheme of geothermal energy extraction. Then, based on cohesion-weakening-friction-strengthening model (CWFS) and literature investigation of granite test at high temperature, the initiation, propagation of excavation damaged zones (EDZs) under unloading and the EDZs scale in EGS-E closed to hydrostatic pressure state is studied. Finally, we have a discussion about the further evolution of surrounding rock stress and EDZs during ventilation is studied by thermal-mechanical coupling. The results show that the influence of high temperature damage on the mechanical parameters of granite should be considered; Lateral pressure coefficient affects the fracture morphology and scale of tunnel surrounding rock, and EDZs area is larger when the lateral pressure coefficient is 1.0 or 1.2; Ventilation of high temperature and high in-situ stress tunnel have a significant effect on the EDZs scale; Additional tensile stress is generated in the shallow of tunnel surrounding rock, and the compressive stress concentration transfers to the deep. EDZs experiences three expansion stages of slow, rapid and deceleration with cooling time, and the thermal insulation layer prolongs the slow growth stage.

Experimental determination of the lateral pressure coefficient in the die of a compacting press by the method of optically active inserts

1974 ◽  
Vol 8 (8) ◽  
pp. 496-499
Author(s):  
V. A. Belousov ◽  
�. �. Kol'man-Ivanov ◽  
I. E. Semenov-Ezhov ◽  
N. A. Stepanov ◽  
I. P. Sukharev
Keyword(s):  
Experimental Determination ◽  
Lateral Pressure ◽  
Pressure Coefficient ◽  
Optically Active ◽  
Lateral Pressure Coefficient

scholarly journals Numerical Simulation on Large Deformation of Weak Rock Mass Tunnel Under High Geostress

2018 ◽  
Vol 175 ◽  
pp. 03025
Author(s):  
Feng Zhou ◽  
Hongjian Jiang ◽  
Xiaorui Wang
Keyword(s):  
Rock Mass ◽  
Large Deformation ◽  
Lateral Pressure ◽  
Simulation Analysis ◽  
Pressure Coefficient ◽  
Surrounding Rock ◽  
Analog Simulation ◽  
Lateral Pressure Coefficient ◽  
High Geostress ◽  
The Stability

The problem about the stability of tunnel surrounding rock is always an important research object of geotechnical engineering, and the right or wrong of the result from stability analysis on surrounding rock is related to success or failure of an underground project. In order to study the deformation rules of weak surrounding rock along with lateral pressure coefficient and burying depth varying under high geostress and discuss the dynamic variation trend of surrounding rock, the paper based on the application of finite difference software of FLAC3D, which can describe large deformation character of rock mass, analog simulation analysis of surrounding rock typical section of the class II was proceeded. Some conclusions were drawn as follows: (1) when burying depth is invariable, the displacements of tunnel surrounding rock have a trend of increasing first and then decreasing along with increasing of lateral pressure coefficient. The floor heave is the most sensitive to change of lateral pressure coefficient. The horizontal convergence takes second place. The vault subsidence is feeblish to change of lateral pressure coefficient. (2) The displacements of tunnel surrounding rock have some extend increase along with increasing of burying depth. The research conclusions are very effective in analyzing the stability of surrounding rock of Yunling tunnel. These are going to be a reference to tunnel supporting design and construction.

scholarly journals Analytical Solution of a Circular Opening considering Nonuniform Pressure and Its Engineering Application

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Peng Wu ◽  
Yanlong Chen ◽  
Liang Chen ◽  
Xianbiao Mao ◽  
Wei Zhang
Keyword(s):  
Analytical Solution ◽  
Plastic Zone ◽  
Young’S Modulus ◽  
Lateral Pressure ◽  
Young's Modulus ◽  
Pressure Coefficient ◽  
Surrounding Rock ◽  
Engineering Practice ◽  
Circular Opening ◽  
Lateral Pressure Coefficient

Based on the Mohr–Coulomb criterion, a new analytical solution of a circular opening under nonuniform pressure was presented, which considered rock dilatancy effect and elastic-brittle-plastic failure characteristics. In the plastic zone, the attenuation of Young’s modulus was considered using a radius-dependent model (RDM), and solution of the radius and radial displacement of plastic zone was obtained. The results show that many factors have important impact on the response of the surrounding rock, including lateral pressure coefficient, dilation coefficient, buried depth, and Young’s modulus attenuation. Under nonuniform pressure condition, the distribution of plastic zone and deformation around the opening show obvious nonuniform characteristic: with the increasing of lateral pressure coefficient, the range of plastic zone and deformation decrease gradually at side, while they increase at roof and floor, and the location of the maximum value of support and surrounding rock response curve transfers from side to roof. Based on the analytical results and engineering practice, an optimization method of support design was proposed for the circular opening under nonuniform pressure.

Study on Influence Factors of Underground Joint Rock Cavern Displacement

2013 ◽  
Vol 353-356 ◽  
pp. 1515-1518
Author(s):  
Zhen Wang ◽  
Chun Han
Keyword(s):  
Lateral Pressure ◽  
Pressure Coefficient ◽  
Influence Factors ◽  
Two Dimensional ◽  
Tunnel Excavation ◽  
Lateral Pressure Coefficient ◽  
Rock Cavern ◽  
The Many ◽  
Rock Tunnel ◽  
Joint Rock

The safety response of joint rock underground tunnels is one of the many problems that draw the attention of geology specialists and scholars. Adopting two dimensional discrete element method, a numerical model of joint rock underground cavern is established to study its stability. The buried depth and the lateral pressure coefficient are considered respectively. The result shows: when the lateral pressure coefficient is identical, the depth is bigger the displacement is more bigger, and the displacement is strong influenced by the buried depth when the lateral pressure coefficient is big; In the same depth the tunnel is buried, the tunnel rocks displacement is slightly influenced by the lateral pressure coefficient when it is small, but the influence is seriously as the lateral pressure coefficient is big. The simulation in the context can be used to provide guide for joint rock tunnel excavation and supporting.

The Effect of Mean Stress Components in High-Cycle, Biaxial Fatigue

2003 ◽  
Vol 31 (2) ◽  
pp. 177-186 ◽  
Author(s):  
Edgar G. Munday
Keyword(s):  
Stress State ◽  
Principal Stress ◽  
Relative Orientation ◽  
New Method ◽  
Mean Stress ◽  
Time Varying ◽  
Biaxial Fatigue ◽  
Stress Components ◽  
The Mean

A new method is presented to obtain the effect of mean stress components in high-cycle, biaxial fatigue. It is assumed that the time-varying stress state can be represented as a superposition of mean components, and proportionally applied alternating components. The method takes into account the relative orientation of the mean and alternating principal stress axes by making the ‘equivalent mean stress’ depend on the alternating components as well as the mean stress components. The method correlates well with the available data. The new method is compared with three popular methods.

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