scholarly journals Application of Double Strength Reduction Factor Method in the Stability Analysis of Rock Slopes

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jiawei Lu ◽  
Jixun Zhang ◽  
Xuhua Ren ◽  
Yunrui Deng
Keyword(s):  
Stability Analysis ◽  
Failure Process ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Rock Slopes ◽  
Reduction Principle ◽  
Strength Reduction Factor ◽  
Factor Method ◽  
Weak Interlayer ◽  
The Stability

The cohesion c and internal friction angle φ play different roles in the progressive failure process of the slope, which indicates that the reduction factors kc and kφ should be different in the calculation. Based on this, the program of double strength reduction factor method was compiled with FISH language, in order to study its application in the rock slopes under different distributions of weak interlayer, and the following conclusions were drawn: (1) the plastic zone calculated by double strength reduction factor method is generally distributed in the weak interlayer, which is basically consistent with the calculation result of the traditional method; (2) the degree to which c and φ play a role is related to the inclination angle of the bottom sliding surface of the unstable block θ. If θ < 45°, φ will play a greater role. If θ ≥ 45°, c will play a greater role; (3) according to the “Pan’s principle,” the matching reduction principle of “kc > kφ” can be adopted when θ < 45°, and the matching reduction principle of “kc < kφ” can be adopted when θ ≥ 45°; (4) the definition of the comprehensive safety factor “K2” in the text is more suitable for the application of double strength reduction factor method in the stability analysis of rock slopes. The applicability of the above conclusions is verified by an actual engineering.

Study on the Stability of Tunnel with Large Cross Section Based on the Ultimate Strength Reduction Method

2014 ◽  
Vol 602-605 ◽  
pp. 590-593
Author(s):  
Hui Chao Zhou ◽  
Rui Jun Liu
Keyword(s):  
Cross Section ◽  
Reduction Method ◽  
Maximum Principal Stress ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Surrounding Rock ◽  
Strength Reduction Method ◽  
Large Cross Section ◽  
Strength Reduction Factor ◽  
The Stability

The stability and the instability form of tunnel surrounding rock have always been hotspot and difficulty problems in underground engineering. We combined the finite element method with the strength reduction method to study the stability of the surrounding rock in tunnel with large cross section. To study the vault settlement, ground settlement and some feature points’ displacement, we used ADINA software to establish a simulation model, from which we can get the relationship between the strength reduction factor and data such as the maximum principal stress and the maximum plastic strain. Also, with analyzing the stability of tunnel surrounding rock, we defined the safety coefficient as 2.5 at last. Then, the tunnel’s weak position during the excavation projects and corresponding strengthening measures can be found through analyzing tunnel stress condition.

scholarly journals Stability Charts for Pseudostatic Stability Analysis of Rock Slopes Using the Nonlinear Hoek–Brown Strength Reduction Technique

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Chaowei Sun ◽  
Junrui Chai ◽  
Tao Luo ◽  
Zengguang Xu ◽  
Yuan Qin ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Slope Angle ◽  
Weighting Factor ◽  
Strength Reduction ◽  
Reduction Technique ◽  
Rock Slope Stability ◽  
Rock Slopes ◽  
Strength Reduction Technique ◽  
Mass Properties ◽  
The Stability

This paper presents a set of stability charts for the stability assessment of rock slopes that satisfy the Hoek–Brown (HB) criterion under various seismic loading conditions. The nonlinear Hoek–Brown strength reduction technique is used to conduct pseudostatic stability analysis of rock slopes subjected to horizontal seismic excitation. Based on an extensive parametric study, first, a set of stability charts with a slope angle of β = 45° under static and pseudostatic conditions are proposed by using ABAQUS 6.10 software. Second, the slope angle weighting factor (fβ) and the seismic weighting factor (fkh) are adopted to characterize the influence of slope angle (β) and horizontal seismic acceleration coefficient (kh) on the rock slope stability. Finally, the reliability of the proposed charts was validated by three typical examples and two case studies, and the results show that the values of the factor of safety (FOS) obtained from the proposed charts are consistent with the values from other methods. The proposed charts provide an efficient and convenient way to determine the FOS of rock slopes directly from the rock mass properties (γ and σci), the HB parameters (mi and GSI), the slope geometry (H and β), and the horizontal seismic coefficients (kh).

Influence of Wear Properties on Fretting Fatigue Life of a CK45 Alloy and the Al7175 Alloy

2008 ◽  
Vol 587-588 ◽  
pp. 971-975 ◽  
Author(s):  
M. Buciumeanu ◽  
A.S. Miranda ◽  
F.S. Silva
Keyword(s):  
Wear Resistance ◽  
Fatigue Life ◽  
Material Properties ◽  
Fatigue Behavior ◽  
Synergetic Effect ◽  
Fretting Fatigue ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
Wear Properties

The main objective of this work was to study the influence of the wear properties of two commercial alloys (CK45 and Al7175) on their fretting fatigue behavior. It is verified the effect of material local degradation by wear on a fatigue strength reduction factor, namely the stress concentration factor, and on the overall fretting fatigue life of these materials. The fretting fatigue phenomenon is a synergetic effect between wear and fatigue. It is dependent on both the fatigue and the wear properties of the materials. Material properties promoting an increase in wear resistance should enhance fretting fatigue life.

Design of Pressure Vessels for Low-Cycle Fatigue

1962 ◽  
Vol 84 (3) ◽  
pp. 389-399 ◽  
Author(s):  
B. F. Langer
Keyword(s):  
Fatigue Strength ◽  
Pressure Vessel ◽  
Low Cycle Fatigue ◽  
Fatigue Curve ◽  
Pressure Vessels ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
The Mean ◽  
Fatigue Evaluation

Methods are described for constructing a fatigue curve based on strain-fatigue data for use in pressure vessel design. When this curve is used, the same fatigue strength-reduction factor should be used for low-cycle as for high-cycle conditions. When evaluating the effects of combined mean and alternating stress, the fatigue strength-reduction factor should be applied to both the mean and the alternating component, but then account must be taken of the reduction in mean stress which can be produced by yielding. The complete fatigue evaluation of a pressure vessel can be a major task for the designer, but it can be omitted, or at least drastically reduced, if certain requirements can be met regarding design details, inspection, and magnitude of transients. Although the emphasis in this paper is on pressure vessel design, the same principles could be applied to any structure made of ductile metal and subjected to limited numbers of load cycles.

Strength reduction factor of self-centering structures under near-fault pulse-like ground motions

2020 ◽  
Vol 24 (1) ◽  
pp. 119-133
Author(s):  
Huihui Dong ◽  
Qiang Han ◽  
Xiuli Du ◽  
Canxing Qiu
Keyword(s):  
Ground Motions ◽  
Time History ◽  
Reduction Factor ◽  
Strength Reduction ◽  
The Self ◽  
Hysteretic Behavior ◽  
Hysteretic Model ◽  
Strength Reduction Factor ◽  
Vibration Period ◽  
Near Fault

Many studies on the strength reduction factor mainly focused on structures with the conventional hysteretic models. However, for the self-centering structure with the typical flag-shaped hysteretic behavior, the corresponding study is limited. The main purpose of this study is to investigate the strength reduction factor of the self-centering structure with flag-shaped hysteretic behavior subjected to near-fault pulse-like ground motions by the time history analysis. For this purpose, the smooth flag-shaped model based on Bouc-Wen model which can show flag-shaped hysteretic behavior is first described. The strength reduction factor spectra of the flag-shaped model are then calculated under 85 near-fault pulse-like ground motions. The influences of the ductility level, vibration period, site condition, hysteretic parameter, and hysteretic model are investigated statistically. For comparison, the strength reduction factors under ordinary ground motions are also analyzed. The results show that the strength reduction factor from near-fault pulse-like ground motions is smaller. Finally, a predictive model is proposed to estimate the strength reduction factor for the self-centering structure with the flag-shaped model under near-fault pulse-like ground motions.

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