Conical Slope Stability of Tertiary Basalt Based on the Geological Cross-Sections

Myeong-Hyeok Ihm; Sung-Pil Hwang; Byung-Suk Park; Jun-Sang An; Woo-Seok Kim

doi:10.9720/kseg.2024.3.447

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2024 Vol.34, Issue 3 Preview Page Next Page

Research Article

Conical Slope Stability of Tertiary Basalt Based on the Geological Cross-Sections 지질횡단면을 활용한 원추형 현무암 비탈면 안정성

30 September 2024. pp. 447-457

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Abstract

This study investigated a cut-slope surface containing Tertiary faults, representing a conical-shaped slope with strike varying from N44°E to NS, N50°W, and finally N70°E. The slope consists mainly of basalt, with discontinuities in the slope including faults, fault zones, fracture zones, shear joints, and extension joints. The type and scale of failure vary with the strike of the slope and the strikes of discontinuities, with plane and wedge failure predominating. Based on face-mapping data, SMR (slope mass rating), rock physical and mechanical properties, analysis of stereonet projections and geological cross-sections, and critical equilibrium analysis, optimal slope stability determination was found to involve the countermeasure method, the slope gradient relief method, the green soil surface treatment method, and a fall prevention measure. After application of the countermeasure method, both dry and wet slope conditions exceeded allowable safety factors. It is expected that the preparation of geological cross-sections of various representative sections perpendicular to the surface of the slope, and the application of corresponding countermeasure methods, will be reasonable tools for three-dimensional analysis of slope stability. If the strike of the slope varies widely, it is necessary to prepare geological cross-sections, and the section used for critical equilibrium analysis must be established as the basic section.

Keywords

conical slope

geological cross-section

slope face-mapping

Tertiary faults

basalts

연구 대상은 신생대 제3기 현무암 지층과 단층 및 파쇄대가 다수 발달하고 있는 절취 암반 비탈면으로서 법면의 주향이 다양하게 변하는 원추형 형상을 나타낸다. 비탈면 내 불연속면은 단층과 단층대 및 파쇄대, 전단절리 및 인장절리가 발달하며, 구간별로 파괴의 유형과 규모는 비탈면 및 불연속면의 배향에 따라 다양하며, 평면파괴와 쐐기파괴가 우세하다. 비탈면 현황도 자료 및 비탈면 암반분류(slope mass rating, SMR), 암석의 물성 및 역학시험, 평사투영법, 지질횡단면도 분석 및 한계평형해석 등을 검토한 결과, 3개의 대표 단면 모두 허용 안전율 미달로 대책공법이 요구되었다. 안전성, 경제성, 시공성 등을 고려한 비탈면 안정성을 위해서는 사면구배완화공법과 함께 녹생토 표면처리 공법 및 낙석방지책 설치를 대책공법의 최적 방안으로 제시하며 적용 후의 비탈면 안전율은 모두 허용안전율 이상이었다. 비탈면 현황도 및 비탈면에 대해 수직인 여러 대표 구간의 지질횡단면도 작성, 대표단면으로 지질횡단면을 이용하여 한계평형 해석 및 대책공법에 대한 제시는 비탈면 3차원 해석과 안정성 검토에 관해 주요한 방법이 될 것으로 생각된다. 원추형 비탈면과 같이 주향이 다양하게 변화하는 경우는 다수의 지질횡단면도 작성이 필요하며, 한계평형해석을 위한 대표 단면은 구간별로 지질횡단면도를 기본도면으로 설정해야 한다.

키워드

원추형 비탈면

지질횡단면도

비탈면 현황도

제3기 단층

현무암

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Information

Publisher :Korean Society of Engineering Geology
Publisher(Ko) :대한지질공학회
Journal Title :The Journal of Engineering Geology
Journal Title(Ko) :지질공학
Volume : 34
No :3
Pages :447-457
Received Date : 2024-09-19
Revised Date : 2024-09-27
Accepted Date : 2024-09-27
DOI :https://doi.org/10.9720/kseg.2024.3.447

The Journal of Engineering Geology ISSN:1226-5268(Print) 2287-7169(Online) 지질공학

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