CHARACTERISTICS OF TOPOGRAPHY - GEOLOGY ALONG HIGHWAY 4B AND LANDSLIDE EVIDENCES

Phí Trường Thành¹, Hồ Thị Thư², Đặng Mỹ Cung³, Nguyễn Thanh Duy⁴

¹Hanoi University of Natural Resources and Environment, ²General Department of Geology and Mineral of Vietnam,

³Ministry of Mineral Resources and Environment, ⁴Vietnam Institute of Geosciens and Mineral Resources

Abstract: This paper presents some results of analyzing the topographic data and geological survey data along the Highway 4B, over 100 km in length by using GIS method, Rock Slope Engineering, Mapinfo software version 10.5 and module Vertical Mapper 3.0 along with the slope angle module which are written from Visual Basic program. The analytical results have indicated that the angle of slope at each cross section varies from 4 to 17 degree, where the slope angle of the southwestern side is always larger than the other side; the highway run through sedimentary rocks of the ages from Triassic to Cenozoic, which are weathered with the thickness of 2 to 5m, along with the high angle slope caused the strong slides at 21 survey sites. Besides, the results of anlyzing the fracture orientation at some survey sites: LS-01, LS-05, LS-06, LS-07, LS-08 and LS-16 determined that they can cause plane failure in here. The model of plane failure is simulated by Rock Plane software and the module which are written in the Visual Basic program showed clearly this type of failure.

Keywords: Cao Bằng - Tiên Yên fault; Highway 4B; Slope angle; Fracture orientation; Plane failure.

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