scholarly journals Sensitivity of Multistage Fill Slope Based on Finite Element Model

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Bingxiang Yuan ◽  
Zihao Li ◽  
Zhilei Su ◽  
Qingzi Luo ◽  
Minjie Chen ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Finite Element ◽  
Internal Friction ◽  
Safety Factor ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Sliding Surface ◽  
Finite Element Software ◽  
The Stability ◽  
Fill Slope

Based on the strength reduction method, the laws of slope displacement and the changing positions of the sliding surface during the filling process are studied. The model of multistage fill slope is established by the finite element software PLAXIS. The difference is compared between the slope with no reinforcement and with reinforcement under the same working condition. Sensitivity analysis is carried out from two aspects which are internal factors and external factors. The finite element analysis shows that the settlement of the multistage fill slope with no reinforcement is mainly concentrated on the right side of the slope and gradually decreases with the increase of the filling height. The position of the sliding outlet is located at the joint of the first and the second grade of the slope. The effect of the reinforcement on the sliding surface is ideal. It is obvious that the reinforcement can supply the slope with a better position of the sliding surface, which is beneficial to the stability of the slope. The sensitivity analysis shows that unit weight, ratio of slope, and height of each grade are negatively correlated with the safety factor. At the same time, the platform width, cohesion, and internal friction angle are positively correlated with the safety factor. The internal friction angle has the greatest influence on the stability of the slope. Besides, the platform width and the height of each grade should be controlled at about 4 m. The sensitivity analysis provides a reference for the design of the multistage filling slope.

scholarly journals Slope stability analysis in the case of probabilistic and semi-probabilistic design method

2019 ◽  
Vol 97 ◽  
pp. 04044
Author(s):  
Hubert Szabowicz
Keyword(s):  
Finite Element ◽  
Internal Friction ◽  
Design Method ◽  
Probability Distributions ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Probabilistic Modelling ◽  
Finite Element Software ◽  
Random Finite Element Method ◽  
Slope Factor

This paper addresses the issue of probabilistic and semi-probabilistic modelling of soil slopes. A slope made of cohesive-frictional soil of specific geometry was analysed as an example. Results were calculated for two methods using the Z-Soil finite element software. It has been assumed that the probability distributions of strength parameters, cohesion and internal friction angle are normal distributions with average values and coefficient of variation = 0.2. Random finite element method (RFEM) has been used for probabilistic modelling. Random fields of cohesion and internal friction angle have been generated using the Fourier series method (FSM). Monte Carlo simulation has been used to calculate the statistics of the slope factor of safety in order to determine the probability of failure. Moreover, assumed parameter distributions allowed to determine safe characteristic values used in the semi-probabilistic partial factors method. Both approaches have been compared in the article.

scholarly journals Study on Impact Parameters of Rigidity and Flexibility for Buried Corrugated Steel Culvert

2014 ◽  
Vol 8 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Baodong Liu ◽  
Zongmin Liu ◽  
Miaoxin Zhang ◽  
Quanlu Wang
Keyword(s):  
Finite Element ◽  
Internal Friction ◽  
Deformation Modulus ◽  
Earth Pressure ◽  
Steel Structures ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Steel Pipe ◽  
Inertia Moment ◽  
Finite Element Program

Buried corrugated steel culverts are universally regarded as a structure with strong deformation adaptability and dispersed the upper load by corrugated steel structures surrounding soil constraints to enhance the carrying capacity and the use of soil-structure interaction. A lot of factors influence the earth pressure of the buried corrugated steel culvert, such as culvert stiffness, physical characteristics of the backfill (bulk density, deformation modulus and internal friction angle), geometry of structure and backfilling height. The finite element program of ANSYS has been used to research the elastic modulus, Poisson’s ratio, internal friction angle of soil, inertia moment of corrugated steel plate and pipe diameter affect the rigidity and flexibility of buried corrugated steel culvert. By defining path lines in the finite element post-processing, extracting and comparing the horizontal and vertical directions soil displacements along the lines, and doing impact pa-rameter analysis. Classification for flexible and rigid pipes of the buried corrugated steel pipe culvert structure has been made according to the analysis results. A theoretical reference has been provided for the design and construction of the buried corrugated steel pipe culverts.

scholarly journals The application of the strength reduction shortest path method to the stability analysis of shallow buried tunnel

2021 ◽  
Author(s):  
Wei Wang ◽  
Jiaqi Zhang ◽  
Ao Liu
Keyword(s):  
Stability Analysis ◽  
Internal Friction ◽  
Shortest Path ◽  
Limit Equilibrium ◽  
Friction Angle ◽  
Strength Reduction ◽  
Surrounding Rock ◽  
Internal Friction Angle ◽  
The Stability ◽  
Shallow Buried Tunnel

Abstract In order to improve the theoretical analysis of surrounding rock stability of shallow buried tunnel. The strength reduction shortest path theory is applied to the stability analysis of shallow buried tunnel surrounding rock, combined with the ultimate equilibrium strength reduction theory. We discussed the influence of the depth and span ratio of tunnel, cohesion, and internal friction angle on the shortest path of the strength reduction, and studied the effects of various factors on shallow buried tunnel safety relationship by using strength reduction factor of safety and the shortest path of the shallow buried tunnel surrounding rock and the grey relational analysis theory. The results show that: In the analysis of shallow buried tunnel in strength reduction, the approximate distribution obeys parabolic between reduction path length and the reduction ratio. When the strength reduction of cohesion is the shortest path the reduction rate is greater than the internal friction angle. The internal friction angle and cohesive force have a great influence on the stability of shallow tunnel under the method of shortest path of strength reduction. Finally, the comprehensive safety factor of shallow buried tunnel calculated by the finite element strength reduction shortest path method is greater than that calculated by the limit equilibrium method.

scholarly journals Mechanism of Embankment Reinforced with Back Berm in Road Engineering

2014 ◽  
Vol 8 (1) ◽  
pp. 853-860
Author(s):  
Wang Qi-Hu
Keyword(s):  
Internal Friction ◽  
Lateral Displacement ◽  
Boundary Value ◽  
Friction Angle ◽  
Nonlinear Finite Element ◽  
Internal Friction Angle ◽  
Nonlinear Finite Element Method ◽  
Road Engineering ◽  
The Stability ◽  
Rock And Soil

Based on the nonlinear finite element method, the mechanism of embankment reinforced with back berm in road engineering reinforced has been studied. It is found there is almost no influence on the value of vertical settlement at the scope of original embankment by back berm. Only the vertical settlement under the location of back berm has been influenced lightly by back berm. The lateral displacement of embankment could be reduced or restrained by back berm. The stability of embankment enhanced when width of back berm enlarged. But the stability of embankment would not be increased any more when the width of back berm achieved its boundary value, so the width of back berm should not be bigger than the boundary value. The stability of embankment enhanced when the value of cohesion or internal friction angle of back berm increased. So rock and soil with big cohesion and internal friction angle should be used to fill back berm preferentially.

Stability Analysis of the Cutting Slope Considering the Influence of Water Content of Soil

2012 ◽  
Vol 204-208 ◽  
pp. 115-118 ◽  
Author(s):  
Qiang Ma ◽  
Heng Lin Xiao ◽  
Qi Zhi Hu ◽  
Li Hua Li
Keyword(s):  
Internal Friction ◽  
Water Content ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Safety Factors ◽  
Strength Parameters ◽  
Direct Shear Tests ◽  
Cutting Slope ◽  
Influence Of Water ◽  
The Stability

Based on the method of strength reduction, numerical simulations were carried out to analyze the stability of the cutting slope. The direct shear tests of slope soil samples with different water content were carried out, and the safety factors of stability of the cutting slope were investigated with different cohesions and internal friction angles. At last, displacements and safety factors of stability of the slope with drains and without drains were calculated, and the observations of displacement of the cutting slope in field were also carried out. The results show that: The water content of the slope soil has great effects on the strength parameters, the cohesion and the internal friction angle decrease with the increase of the water content, and the effect is more significant on the cohesion than that on the internal friction angle. The safety factor of stability for the slope increases with the increase of the strength parameters, hence it increases with the decrease of the water content. The section of the slope without drains in the field is unstable, while the section with drains maintains stable.

Back-analysis of geophysical flows using three-dimensional runout model

2018 ◽  
Vol 55 (8) ◽  
pp. 1081-1094 ◽  
Author(s):  
R.C.H. Koo ◽  
J.S.H. Kwan ◽  
C. Lam ◽  
G.R. Goodwin ◽  
C.E. Choi ◽  
...  
Keyword(s):  
Finite Element ◽  
Internal Friction ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Three Dimensional ◽  
Friction Angle ◽  
Geophysical Flows ◽  
Internal Friction Angle ◽  
Case Histories

Predicting the mobility and delineating the extent of geophysical flows remains a challenge for engineers. The accuracy of predictions hinges on the reliability of input parameters of runout models. Currently, limited field data for landslide case histories are available for benchmarking the performance of runout models. Key rheological parameters, such as the equivalent internal friction angle, cannot be measured directly using laboratory experiments and must instead be determined through back-analyses. A series of dynamic back-analyses was carried out for notable landslide case histories in Hong Kong, accounting for the effects of pore-water pressure on the equivalent internal friction angle, using a three-dimensional finite-element mobility model. The recorded and simulated run-out distances, as well as lateral spreading, were compared. Results reveal that the back-analysed equivalent internal friction angles resulting from open-hillslope failures and from channelized geophysical flows range from 25° to 30° and 15° to 20°, respectively. This is attributed to incised geophysical flow channels having an elevated water head and higher degree of saturation compared to open-hillside slope surfaces, wherein the induced elevated pore-water pressure profoundly lowers the equivalent internal friction angle. The back-calculated values may be useful for finite-element-based design of mitigation measures.

Sensitivity Analysis of Loess Cave Dwellings’ Random Variables

2012 ◽  
Vol 170-173 ◽  
pp. 1234-1237
Author(s):  
Yong Wei ◽  
Ping Gong Guo
Keyword(s):  
Sensitivity Analysis ◽  
Standard Deviation ◽  
Internal Friction ◽  
Random Variables ◽  
Structural Response ◽  
Random Variable ◽  
Relative Sensitivity ◽  
Friction Angle ◽  
Henan Province ◽  
Internal Friction Angle

The relative sensitivity of loess cave dwellings’ random variables is researched. The random variables are divided to resistance terms and load terms. The structural response is analyzed on standard deviation intervals with every random variable, and the gradient of structural response on each standard deviation interval is used to evaluate the sensitivity of random variables. The random variables research of loess cave dwellings in Shan city, Henan province shows that, the sensitivity of cohesion and cave leg width are the biggest, and internal friction angle and span of cave are the smallest which can be treated as constant parameters.

Characterization of Shear Strength and Interface Friction of Organic Soil

2020 ◽  
Vol 857 ◽  
pp. 203-211
Author(s):  
Majid Hamed ◽  
Waleed S. Sidik ◽  
Hanifi Canakci ◽  
Fatih Celik ◽  
Romel N. Georgees
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Internal Friction ◽  
Moisture Content ◽  
Water Content ◽  
Friction Angle ◽  
Structural Materials ◽  
Organic Soil ◽  
Internal Friction Angle ◽  
Interface Friction

This study was undertaken to investigate some specific problems that limit a safe design and construction of structures on problematic soils. An experimental study was carried out to examine the influence of loading rate and moisture content on shear strength of organic soil. Influece of moisture content on interface friction between organic soil and structural materials was also attempted. A commonly used soil in Iraq was prepared at varying moisture contents of 39%, 57% and 75%. The experimental results showed that the increase in water content will decrease the shear stress and the internal friction angle. An increase of the shearing rate was found to decrease the shear stress and internal friction angle for all percetanges of water contents. Further, direct shear tests were carried out to detect the interface shear stress behavior between organic soil and structural materials. The results revealed that the increase in water content was shown to have significant negetavie effects on the interface internal friction and angle shear strength.

scholarly journals Influence of Structural Plane Microscopic Parameters on Direct Shear Strength

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yanhui Cheng ◽  
Weijun Yang ◽  
Dongliang He
Keyword(s):  
Particle Size ◽  
Shear Strength ◽  
Internal Friction ◽  
Direct Shear Test ◽  
Shear Test ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Direct Shear ◽  
Stiffness Ratio ◽  
Structural Plane

Structural plane is a key factor in controlling the stability of rock mass engineering. To study the influence of structural plane microscopic parameters on direct shear strength, this paper established the direct shear mechanical model of the structural plane by using the discrete element code PFC2D. From the mesoscopic perspective, the research on the direct shear test for structural plane has been conducted. The bonding strength and friction coefficient of the structural plane are investigated, and the effect of mesoscopic parameters on the shear mechanical behavior of the structural plane has been analyzed. The results show that the internal friction angle φ of the structural plane decreases with the increase of particle contact stiffness ratio. However, the change range of cohesion is small. The internal friction angle decreases first and then increases with the increase of parallel bond stiffness ratio. The influence of particle contact modulus EC on cohesion c is relatively small. The internal friction angle obtained by the direct shear test is larger than that obtained by the triaxial compression test. Parallel bond elastic modulus has a stronger impact on friction angle φ than that on cohesion c. Under the same normal stress conditions, the shear strength of the specimens increases with particle size. The shear strength of the specimen gradually decreases with the increase of the particle size ratio.

Sign in / Sign up

Export Citation Format

Share Document