A Thermo-Hydro-Mechanical Coupled Numerical Simulation on the FE Experiment: Step 1 Simulation in Task C of DECOVALEX-2023

Taehyun Kim; Chan-Hee Park; Changsoo Lee; Jin-Seop Kim

doi:10.7474/TUS.2022.32.6.518

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2022 Vol.32, Issue 6 Preview Page Next Page

Original Article

A Thermo-Hydro-Mechanical Coupled Numerical Simulation on the FE Experiment: Step 1 Simulation in Task C of DECOVALEX-2023 Mont Terri FE 실험 대상 열-수리-역학 복합거동 수치해석: DECOVALEX-2023 Task C 내 Step 1 수치해석 연구

31 December 2022. pp. 518-529

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Abstract

In Task C of the DECOVALEX-2023 project, nine institutes from six nations are developing their numerical codes to simulate thermo-hydro-mechanical coupled behavior for the FE experiment performed at Mont Terri underground rock laboratory, Switzerland. Currently, Step 1 for comparing the simulation results to field data is the ongoing stage, and we used the OGS-FLAC simulator for a series of numerical simulations. As a result, temperature increase depending on the heating hysteresis was well simulated, and saturation variation in the bentonite depending on phase change was observed. However, due to the suction overestimation, relative humidity and temperature change in the bentonite and the pressure variation in the Opalinus clay showed a difference compared to the field data. From the observation, it is confirmed that the effect of the bentonite capillary pressure is dominant to the flow analysis in the disposal system. We further plan to draw improved results considering tunnel support material and accurate initial water pressure distribution. Additionally, the thermal, hydrological, and mechanical anisotropy of the Opalinus clay was well simulated. From the simulation results, we confirmed the applicability of the OGS-FLAC simulator in the disposal system analysis.

Keywords

DECOVALEX-2023 Task C

OGS-FLAC

Multi-phase flow

Thermo-Hydro-Mechanical coupled behavior

DECOVALEX-2023 Task C에서는 6개국 9개 참여 기관들이 스위스 Mont Terri 지하처분연구시설에서 수행된 FE 실험을 대상으로 열-수리-역학 복합거동 모사를 위한 해석코드 개발을 수행하고 있다. 현재 현장시험 결과와 비교 분석을 위한 Step 1이 진행되고 있으며, 본 연구진은 OGS-FLAC 해석 시뮬레이터를 활용하여 일련의 해석을 진행하였다. 해석 결과 히터 가열에 따른 온도 상승이 잘 구현되었고, 상변화에 따른 완충재 내 포화도 변화를 관측할 수 있었다. 반면 완충재 흡입력의 과대평가로 완충재 내 상대습도, 온도 변화 및 Opalinus 점토암 내 압력 변화가 현장 결과와 다소간 차이를 나타내는 것을 확인하였다. 이를 통해 완충재 흡입력이 처분시스템 해석 시 유동 해석 결과에 지배적인 영향을 미침을 확인할 수 있었으며, 향후 지보재 및 초기 수압 모사 개선을 통해 향상된 결과를 도출하고자 한다. 또한, Opalinus 점토암의 열, 수리, 역학적 이방성이 잘 구현되었으며 해석 결과를 통해 OGS-FLAC 시뮬레이터의 처분시스템 해석 적용성을 확인하였다.

키워드

DECOVALEX-2023 Task C

OGS-FLAC

다상유동

열-수리-역학 복합거동

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Information

Publisher :Korean Society for Rock Mechanics and Rock Engineering
Publisher(Ko) :한국암반공학회
Journal Title :Tunnel and Underground Space
Journal Title(Ko) :터널과 지하공간
Volume : 32
No :6
Pages :518-529
Received Date : 2022-12-09
Revised Date : 2022-12-12
Accepted Date : 2022-12-13
DOI :https://doi.org/10.7474/TUS.2022.32.6.518

Tunnel and Underground Space ISSN:1225-1275(Print) 2287-1748(Online) 터널과 지하공간

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