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2026 Vol.27, Issue 4 Preview Page
Analysis of the Relationship between Pore Flow-Path Characteristics and Hydraulic Conductivity in Random Packings of Spherical Particles

구형 입자의 무작위 패킹에 따른 공극의 유로 특성과 투수계수의 연관성 분석

Jae-Eun Ryou1
,
Seokgu Gang2
,
Jongwon Jung3*
유 재은1
,
강 석구2
,
정 종원3*
1Assistant Professor, School of Civil Engineering, Chungbuk National University
2Ph.D, Department of Civil Engineering, Chungbuk National University
3Professor, School of Civil Engineering, Chungbuk National University
*Corresponding Author
1 April 2026. pp. 13-20
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Abstract

The hydraulic conductivity of granular media is governed not only by porosity but also by the development of flow-contributing connected pathways, the presence of bottlenecks, and the spatial arrangement of the pore structure. In this study, multiple random packing specimens were generated under identical conditions, and hydraulic conductivity was evaluated using pore-network-based flow simulations. We then compared and validated the effectiveness of microstructural descriptors in explaining variations in permeability. The results show that conductivity generally increases with porosity- and local-porosity-related indicators, confirming that the concentration and distribution of flow-effective pore space are more influential than the total void volume alone. In addition, a chord-length descriptor representing streamwise continuity increases with hydraulic conductivity, indicating that long, continuous pathways along the flow direction reduce hydraulic resistance. In contrast, increasing asymmetry and extremeness in the pore (or throat) size distribution tends to decrease hydraulic conductivity, while a characteristic radius sensitive to small constrictions highlights the dominant role of bottleneck narrowing. Furthermore, compared with porosity-based empirical formulations, a set of eight key microstructural descriptors that jointly represent connectivity, bottlenecks, local channelization, and distributional asymmetry improves the explanatory power for hydraulic conductivity. Overall, the permeability of random packings can be interpreted as a competition between enhancing factors associated with pathway development and directional continuity, and reducing factors associated with bottlenecks and structural heterogeneity. The proposed descriptor framework can support the development of structure-informed predictive equations and design/evaluation models for hydraulic conductivity.

Keywords
Random packing
Pore network model
Hydraulic conductivity
Microstructural descriptors
Connectivity
Bottleneck effect

입상체의 투수계수는 공극률뿐 아니라 유동에 실제로 기여하는 연결 경로의 발달, 병목 구조의 존재, 그리고 공극 구조의 공간적 배열에 의해 좌우된다. 본 연구에서는 동일한 생성 조건에서 다수의 무작위 패킹 시료를 구축한 뒤, 공극 네트워크 기반 유동 시뮬레이션으로 투수계수를 산정하고, 투수성 변화를 설명하는 미시구조 지표의 유효성을 비교·검증하였다. 분석 결과, 공극률 및 국부 공극률 관련 지표가 증가할수록 투수계수가 전반적으로 증가하여, 전체 공극량보다 유효 유로의 집중과 분포 특성이 중요함을 확인하였다. 또한 x 방향 연속성을 대변하는 공극 현 길이 지표가 클수록 투수계수가 증가해, 유동 방향으로 이어지는 연결 경로가 유동 저항을 완화하는 핵심 요인임을 보였다. 반면 공극(또는 throat) 크기 분포의 비대칭성 및 극단성이 커질수록 투수계수가 감소하는 경향이 나타났고, 작은 크기에 민감한 대표 반경 지표는 병목 협착의 지배 가능성을 시사하였다. 나아가 공극률 중심 경험식과 비교하여, 연결성·병목·국부 채널화·분포 비대칭성을 함께 반영하는 8개 핵심 미시지표 조합이 투수계수 예측의 설명력을 개선할 수 있음을 확인하였다. 종합하면, 무작위 패킹 시료의 투수성은 방향성 연속성과 유효 유로 발달에 의한 증가 요인과, 병목 및 구조적 불균질성에 의한 감소 요인의 경쟁으로 설명될 수 있으며, 제안 지표 체계는 구조 기반 투수 예측식 및 설계·평가 모델 개발에 활용될 수 있다.

키워드
랜덤 패킹
공극 네트워크 모델
투수계수
미시구조 지표
연결성
병목 효과
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Information
  • Publisher :Korean Geo-Environmental Society
  • Publisher(Ko) :한국지반환경공학회
  • Journal Title :Journal of the Korean Geo-Environmental Society
  • Journal Title(Ko) :한국지반환경공학회 논문집
  • Volume : 27
  • No :4
  • Pages :13-20
  • Received Date : 2026-01-28
  • Revised Date : 2026-02-06
  • Accepted Date : 2026-02-10
  • DOI :https://doi.org/10.14481/jkges.2026.27.4.13
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