Element Failure Risk Assessment of Soil Slope
Publication: International Journal of Geomechanics
Volume 23, Issue 9
Abstract
Two traditional methods when calculating slope failure risk (R) are the rigid body limit equilibrium (LEM) and finite-element methods (FEM). However, the LEM requires the previous assumption of the location and shape of the sliding surface; and the FEM needs to carry out postprocessing to estimate the slope sliding surfaces. This paper proposed an element failure risk method (EFR) to calculate R based on plastic limit analysis. The proposed method did not require any assumptions about the failure modes. The safety factors and velocity fields were first computed based on the stochastic programming model that used random soil shear strength parameters. The failure of the elements and R was evaluated and calculated. An efficient upper bound method (UBM) parallel computation was programmed based on Python, which enhanced computational efficiency. Two classic cases were conducted to validate the proposed method. The results showed that the proposed method could accurately calculate the probability and R. This broadened the applications of the EFR method in the risk assessment of slope stability.
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Acknowledgments
This work is supported by the National Natural Science Foundation of China (Grant No. 12162018 and 12262016).
Notation
The following symbols are used in this paper:
- Ae
- area of element e (m2);
- ab
- coordinate transformation matrix of finite element b on the boundary;
- matrix of plastic flow constraint conditions of velocity d;
- matrix of plastic flow constraint conditions of velocity d;
- matrix of plastic flow constraint conditions of finite element e;
- matrix of plastic flow constraint conditions of finite element e;
- Ce
- failure consequence coefficient of finite element e;
- Cf
- failure consequence coefficient of the slope;
- Ci
- failure consequence coefficient of the ith failure mode;
- I[tm]
- failure function of the slope that corresponded to the random number of the shear tmth parameter;
- Ie[tm]
- failure function of finite element e that corresponded to the random number of the shear tmth parameter;
- km
- random variable of safety factor;
- random variable of overload factor of volume weight;
- Nb
- number of finite elements on the boundary of the soil slope;
- Nd
- number of velocity d in the soil slope;
- Ne
- number of finite elements in the soil slope;
- Nf
- number of failure modes;
- Nm
- quantity of material for the soil cohesion and the friction angle of the Monte Carlo random number;
- P[km(x)]
- failure probability of the failure mode that corresponded to the safety factor of km(x);
- Pf
- failure probability of the slope;
- Pf,e
- failure probability of finite element e;
- Pf,i
- failure probability of ith failure mode;
- Pf,e∈Part1
- failure probability of finite element in Part 1;
- Pf,Part1
- failure probability in Part 1;
- Pf,e∈Part2
- failure probability of finite element in Part 2;
- Pf,Part 2
- failure probability in Part 2;
- Pf,e∈Part3
- failure probability of finite element in Part 3;
- Pf,Part3
- failure probability in Part 3;
- Pf,e∈Part4
- failure probability of finite element in Part 4;
- Pf,Part4
- failure probability in Part 4;
- Pf,e∈Partx
- failure probability of elements that included all x-failure modes;
- pore water pressure of triangular element e;
- R
- failure risk of the slope;
- Re
- failure risk of finite element e;
- Ri
- failure risk of ith failure mode;
- velocity vector of boundary finite element b;
- velocity vector of velocity d;
- velocity vector of finite element e;
- the centroid velocity of finite element e;
- velocity of the kth node (k = 1, 2, 3, 4) on velocity d plane in x-direction;
- velocity of nodes j (j = 1, 2, 3) in finite element e in x-direction;
- velocity of the kth node (k = 1, 2, 3, 4) on velocity d plane in y-direction;
- velocity of nodes j (j = 1, 2, 3) in finite element e in y-direction;
- internal power of finite element;
- external work power of pore water pressure in element continuous body;
- internal power of velocity d;
- external work power exerted by pore water pressure on velocity d;
- external work power exerted by the dead weight on velocity of element nodes;
- Z
- limit state function of slope;
- vector of nonnegative plastic multiplier of velocity d; and
- vector of nonnegative plastic multiplier of finite element e.
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© 2023 American Society of Civil Engineers.
History
Received: Oct 16, 2022
Accepted: Mar 26, 2023
Published online: Jun 28, 2023
Published in print: Sep 1, 2023
Discussion open until: Nov 28, 2023
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