SUMMARY

Analyzing the danger of landslide in the Gi Pass area, Ngn Sơn District, Bắc Cạn Province

Đỗ Minh Đức, Đặng Quang Khang

The Gi Pass area is characterized by strongly dissected relief and unfavourable geological structure for the slope stabilization. In the Highway 3 section passing through the Gi Pass, there usually occur grave landslides in both positive and negative talus. When there is big rain, rocks and soil in the pass are carried away with significant quantity along small streams and discharged to lowland areas, threatening the safety of many houses in the Mạch Village. The study of geology, geomorphology, physico-mechanical characters of rocks and soil and the analysis of slope stabilization have been determining 22 great blocks of slide, among them there are 4 blocks in the negative talus. The slope stabilization in this area can be lost when the rainfall reaches 100 mm and landslide occurs strongly when the rainfall reaches up to 150 mm. Large occurring slided blocks will fill lowland areas through 8 different mud and rock flows. These flows empty into a large stream flowing through the Mạch Village, threatening the safety of people. This is an important basis affirming the necessity of moving families lying in dangerous areas, situated from the left bank of the Bản Mạch Stream to the opposite hill area. Besides, an association of engineering measures, such as decrease of loading capacity and construction of rock barrage or blocking walls, is also suggested with the aim of processing concrete slide blocks.

Người bin tập: TS. Hong Anh Khiển.