ANSYS-Based Software Development and Application of Seismic

Dynamic Response Finite Element Calculation Platform for

Earth-Rockfill Dams

Jing Liu

, Shengjie Di and Liwen Deng

Northwest Engineering Corporation Limited, Power China, Xi’an 710065, Shaanxi, China

Keywords: ANSYS, Earthquake, Finite Element, Earth-Rockfill Dam.

Abstract: Earthquake is an important factor affecting the operation safety of earth-rockfill dams. At present, the

numerical calculation of earthquake conditions of earth-rockfill dams is still based on mature finite element

commercial software, which is inconvenient in research, learning and practical application. Accordingly,

this paper introduces the finite element calculation platform of earth-rockfill dam seismic dynamic based on

ANSYS. The platform is written in Fortran language, with good user interaction and visual UI interface.

The actual engineering example test shows that the results are in line with the general dynamic displacement

and deformation laws of the engineering level earth-rockfill dam under seismic conditions, which verifies

the accuracy of the calculation results of the platform, and has a certain promotion value.

https://orcid.org/0009-0003-2095-6560

1 INTRODUCTION

In the past 40 years, China's earth-rockfill dam

engineering has made rapid progress and is

developing towards ultra-high earth-rockfill dams

and complex natural conditions (Zhou et al., 2019).

However, observation and research on some

completed earth-rockfill dams both domestically and

internationally have shown that earth-rockfill dams

often experience problems such as soil sliding,

cracking, and leakage after earthquake action (Ye,

2022; Chen, 2009), which poses hidden dangers to

the long-term operation safety of earth-rockfill

dams. Therefore, how to accurately calculate the

dynamic displacement and stress distribution of the

dam body under earthquake response has gradually

become a hot research topic in the seismic design of

earth-rockfill dams.

At present, the quasi-static method and time-

history analysis method are mainly used to calculate

the seismic dynamic response of earth-rockfill dams.

Because the quasi-static method does not consider

the influence of factors such as ground motion

spectrum characteristics and duration, it is not

suitable to guide the seismic design of high earth-

rockfill dams in a strict sense. The factors

considered by time-history analysis method are more

comprehensive, but there is no consensus on

dynamic parameters, seismic wave input mode and

other aspects in the actual calculation, which has a

great impact on the calculation results (Niu, 2017).

In addition, the calculation process still relies on a

mature commercial finite element platform, which

has problems such as high learning cost and

complex modeling in practical application (Guan et

al., 2023).

In this regard, a finite element calculation

platform for seismic dynamic response of earth-

rockfill dams is developed based on ANSYS. The

platform is written in Fortran language, and the

efficiency is improved by using parametric modeling

and analysis method through secondary development

technology. In the calculation, a variety of strength

and constitutive models can be selected to realize the

control of multi condition and multi task calculation

process. The platform uses a preprocessing

conjugate gradient solver independently developed,

which is significantly more efficient than most

popular solvers, and can solve the problem of tens of

millions of degrees of freedom on a microcomputer;

At the same time, it has a relatively perfect pre-

202

Liu, J., Di, S., Deng and L.

ANSYS-Based Software Development and Application of Seismic Dynamic Response Finite Element Calculation Platform for Earth-Rockﬁll Dams.

DOI: 10.5220/0013627700004671

In Proceedings of the 7th International Conference on Environmental Science and Civil Engineering (ICESCE 2024), pages 202-207

ISBN: 978-989-758-764-1; ISSN: 3051-701X

processing and post-processing and visual interface,

and can easily output displacement, stress and stress

level contour map, liquefaction index, failure mode

map, deformation contour map, etc. through menu

operation, which is convenient for the analysis and

collation of results, and the user experience is good.

2 GENERAL IDEA AND

TECHNICAL ROUTE OF

SOFTWARE

The software is developed based on ANSYS

mechanical APDL platform, and its main functions

include parametric modeling of earth-rockfill dam,

pre-processing of finite element model, seismic

dynamic calculation and post-processing of results.

For seismic dynamic analysis, quasi-static method

and seismic wave time-history analysis method can

be used to study the permanent settlement of

earthquake. The realization ideas of each function

are as follows:

2.1 Parametric Modeling Module of

Earth-Rockfill Dam

The platform has developed data interfaces with

commercial finite element software such as

ABAQUS, ANSYS, FLAC3D, etc. to facilitate the

import and conversion of external model data. At the

same time, the platform developed relatively

convenient parametric modeling functions for

homogeneous dam, concrete face dam, clay core

dam and asphalt core dam.

(

)

(

Figure 1: Parametric modeling interface and grid model.

As shown in Figure 1(a), user can set control

parameters such as earth-rockfill dam type, model

scale, upstream and downstream slope and bottom

width in the visual UI interface, and click "OK" to

quickly generate the finite element calculation grid

file for this platform. After the model is generated,

user can call Tecplot to open the export file to check

the calculation grid model of earth-rockfill dam in

Figure 1(b).

2.2 Model Preprocessing and

Calculation Process Setting

After importing the earth-rockfill dam calculation

grid model, user can carry out various preparations

for calculation in the UI interface of the "model

preprocessing" module. For seismic dynamic

calculation, it mainly includes material parameter

setting, seismic wave input and calculation process

setting, etc.

The material parameters and seismic wave

acceleration for dynamic calculation are imported

into the platform from the prepared parameter

sample table. User can zoom and output the seismic

wave acceleration in the UI interface.

Figure 2(a) and (b) show the definition interface

of parameters related to quasi-static method and

seismic wave input time history method for seismic

dynamic calculation of earth-rockfill dams, where

users can select dynamic calculation methods and set

parameters. After setting, click "OK" to start running

the calculation program.

ANSYS-Based Software Development and Application of Seismic Dynamic Response Finite Element Calculation Platform for

Earth-Rockﬁll Dams

203

(a) (

)

Figure 2: Preprocessing settings for dynamic calculation of earth-rockfill dams.

2.3 Theory and Method for Seismic

Dynamic Calculation and Analysis

of Earth-Rockfill Dams

2.3.1 Constitutive Model for Dynamic

Calculation

In order to simulate the dynamic characteristics of

soil and stone, an equivalent linear model is used. In

the equivalent linear model, the soil is regarded as a

viscoelastic body, and the two parameters of

equivalent elastic modulus and equivalent damping

ratio are used to reflect the nonlinear and hysteretic

characteristics of the dynamic stress-strain

relationship of soil, and the elastic modulus and

damping ratio are expressed as functions of dynamic

strain amplitude. At the same time, the influence of

the average principal stress of static consolidation is

considered in determining the above relationship,

and the specific expression is:

max

γγ

(1)

max

(1 / )

rdr

γγγ

(2)

max

is initial maximum shear modulus,

dynamic shear modulus,

is dynamic shear strain,

is maximum equivalent damping ratio, generally

determined by empirical formula.

The maximum shear modulus of soil can be

expressed as:

max 1

()

GkP

(3)

is initial average consolidation stress,

and

are test constant, related to soil type and bulk

density.

is atmospheric pressure.

The maximum shear stress of soil under dynamic

conditions is:

1/2

max 1 0 0

sin cos

τλ σϕ ϕ σ





=+−











)

is dynamic correction factor,

is coefficient

of static lateral pressure of soil,

=1-sinK

and

are cohesion and internal friction angle of soil.

2.3.2 Establishment and Solution of

Dynamic Equation

Only under the action of seismic force, the relative

motion equation of the whole system of earth-

rockfill dam and overburden can be discretized into

the following matrix equation form:

{} {} {} { }

Mu Cu Ku Mu++ =−

  

)

{}u



, {}u



and {}u are the acceleration vector,

velocity vector and displacement vector of the

system.

M ,

and K are the respectively the mass

matrix, damping matrix and stiffness matrix of the

system.

{}



is the input seismic acceleration.

Assuming that the system obeys the Rayleigh

damping relationship, the damping matrix can be

expressed as a linear combination of mass matrix

and stiffness matrix:

CMK

αβ

(6)

and

are Rayleigh damping coefficient,

αλω

βλω

is the first order natural

circular frequency.

ICESCE 2024 - The International Conference on Environmental Science and Civil Engineering

204

The vibration mode superposition method and

direct integration method are often used to solve the

above dynamic equations. Due to the strong

nonlinear characteristics of soil, the platform solver

uses Newmark integral method to solve.

2.3.3 Analysis Method of Seismic Residual

Deformation

The softening modulus method is used to calculate

the permanent deformation of the dam body. Its

basic concept is that the seismic action reduces the

modulus of soil mass, resulting in residual

deformation. It is assumed that the stress-strain

relationship of the soil after the earthquake still

conforms to the Duncan Chang hyperbolic

relationship, and the stress state of the soil element

before and after the earthquake remains unchanged,

but the strain increases the seismic residual strain on

the basis of the original initial strain, which can be

deduced from the stress coordination condition:

()

ii ip i p

εεε

)

is elastic modulus of soil before earthquake,

E is elastic modulus of soil after earthquake.

Further considering the factors such as short

duration of earthquake and undrained soil, the

Poisson's ratio of soil after earthquake can be

obtained as follows:

1(12) /

ip i ip i

μμε



=−−



)

According to the static balance equation, the

seismic permanent deformation of the dam is the

difference between the deformation before and after

the earthquake, that is, the residual permanent

deformation of the dam is:

pipi

uuu=−

)

CALCULATION VERIFICATION

AND ENGINEERING

APPLICATION

3.1 Project Overview

The maximum dam height of a core rockfill dam is

83.0m, the upstream dam slope ratio is 1:2.0, and the

downstream average dam slope ratio is 1:1.8. The

lowest foundation elevation of the core wall is

3121.50m, the dam crest elevation is 3204.5m, the

width is 12.50m, and the axial length of the dam is

about 230m. According to the seismic risk analysis

report of the dam site area, the peak horizontal

acceleration of bedrock with a 100-year probability

of exceeding 2% is taken as 2.44m/s

, the peak

vertical seismic acceleration is taken as 2/3 of the

horizontal direction, and the calculation time step is

taken as 0.02s. The finite element calculation model

is shown in Figure 3.

Figure 3: Finite element model.

In this calculation, the time-history analysis

method of input seismic wave is used to study the

maximum dynamic displacement, maximum

dynamic acceleration and dynamic shear stress

distribution of the dam along the river and in the

vertical direction under the action of ground motion

load.

3.2 Seismic Dynamic Calculation

Results

According to the Figure 4, the dynamic

displacement of the dam body increases with the

distance to the dam foundation, reaching the

maximum at the top of the dam. The maximum

displacement of the dam body along the river is

7.5cm, which occurs in the center of the dam crest of

the riverbed profile. The maximum vertical dynamic

displacement is about 2.0cm, which occurs in the

upstream dam slope area near the dam crest.

In addition, Figure 5 shows that the dam body

has obvious acceleration amplification effect during

the earthquake. The maximum response acceleration

of the dam body gradually increases with the

increase of elevation, and gradually increases from

the inside of the dam body to the upstream and

downstream surfaces. The acceleration reaches the

peak at the top of the dam.

Figure 6 shows that the maximum dynamic shear

stress is 0.1~1.2MPa. There is a certain

concentration of dynamic shear stress in the corridor

at the bottom of the core wall, and the extreme value

ANSYS-Based Software Development and Application of Seismic Dynamic Response Finite Element Calculation Platform for

Earth-Rockﬁll Dams

205

is about 1.2MPa, which occurs at the top of the

corridor.

(

)

(

)

Figure 4: Maximum seismic response dynamic displacement.

Figure 5: Maximum seismic response dynamic acceleration.

Figure 6: Maximum seismic response dynamic shear stress.

Based on the above results, it can be seen that the

core rockfill dam of the project meets the seismic

requirements on the whole under the action of

earthquake, and the design of the core rockfill dam

is reasonable, and no problems of incongruous

deformation and excessive extreme deformation are

found, indicating that the core rockfill dam has good

seismic performance. The maximum response

dynamic displacement and dynamic shear stress

distribution of the dam body in the calculation

results conform to the seismic response distribution

law of the core wall dam of this engineering level,

which indicates that the seismic dynamic calculation

of the actual earth-rockfill dam project by this

platform is feasible and reliable.

4 CONCLUSION

This paper introduces the main functions and

technical route of the finite element calculation

platform for seismic dynamic response of earth-

rockfill dam based on ANSYS, as well as its

application in the seismic dynamic response

calculation of a core rockfill dam project. and the

mainly conclusions are as follows:

(1) The finite element calculation platform of

earth-rockfill dam seismic dynamic response based

on ANSYS has convenient function modules and

user-friendly visual interface. Compared with the

commercial finite element software platform, it can

greatly simplify the process and improve the

calculation efficiency.

ICESCE 2024 - The International Conference on Environmental Science and Civil Engineering

206

(2) The seismic dynamic calculation test of a

domestic core rockfill dam project is carried out, and

the calculation results accord with the seismic

response distribution law of the project level core

dam, which verifies the reliability and accuracy of

the calculation results of the software platform, and

has certain popularization value.

ACKNOWLEDGMENTS

This work was financially supported by the major

science and technology project of Northwest

Engineering Corporation Limited, Power China. In

the meantime, we express thanks to our colleagues

for their help and technical support.

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Earth-Rockﬁll Dams

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