What do experts say about the risk of landslides at Hon Trong Mai in Ha Long Bay?

"Diagnosing" the Rooster and Hen Islet

At the workshop on the conservation of Trong Mai islets in Ha Long Bay, Dr. Quach Duc Tin, Deputy Director of the Institute of Geological Sciences and Mineral Resources, said that the workshop aimed to receive comments and exchanges from scientists and managers related to the conservation of Trong Mai islets in Ha Long Bay.

Rooster and Hen Islet on Ha Long Bay

The workshop has 6 main research topics presented by experts from the Institute of Geosciences and Mineral Resources, Institute of Water Resources Sciences, and Norwegian Geotechnical Institute.

MSc. Ho Tien Chung, Deputy Head of the Tectonics and Geomorphology Department, Institute of Geosciences and Mineral Resources, said that in Ha Long Bay, geological and geodynamic processes are still taking place, causing many changes to the islands and caves. Hon Trong Mai consists of two small rocky islands shaped like a pair of roosters and hens, about 13.9 m high, with the island's legs tapering to create a precarious position.

Through the process of geological and tectonic activities and the impact of sea water, Hon Trong Mai has a monoclinic structure with many systems of cracks that pose a risk of landslides, landslides or deformation, causing the loss of the symbolic image of the world heritage Ha Long Bay. Therefore, it is necessary to study and preserve it.

A corner of Ha Long Bay

Dr. Tran Diep Anh, researcher at the Department of Tectonics and Geomorphology, Institute of Geosciences and Mineral Resources, said that the results of detailed investigation and measurement of the Hon Trong Mai area combined with satellite image analysis, 3D model building... have determined that there are 40 blocks at risk of landslides and collapse in the Hon Trong Mai area. Of which, Hon Trong has 11 blocks and Hon Mai has 29 blocks.

A total of 13 blocks are at risk of flat sliding (Hon Trong 6, Hon Mai 7); 4 blocks are at risk of wedge sliding (Hon Trong 3, Hon Mai 1); 23 blocks are at risk of landslides and toppling (Hon Trong 3, Hon Mai 21)...

Dr. Tran Diep Anh assessed that the results obtained were quite detailed and were an important product for the design of pre-feasibility solutions to minimize the risk of landslides and collapses, thereby creating favorable conditions for stabilizing Trong Mai Islet.

How to preserve the Rooster and Hen Islet?

From research, investigation and assessment of the current status of Trong Mai Islet, MSc. Ho Sy Mao, researcher at the Institute of Water Resources Science, presented in detail the engineering solutions for each object at Trong Mai Islet.

Preserving the Rooster and Hen Islets in Ha Long Bay is not an easy task.

Accordingly, the proposed solutions for each specific subject are geological formations above water level, in tidal zones and completely below sea level.

For each subject, the author proposed specific technical measures such as using anchors to protect sliding blocks, pumping cement into cracks, building load-bearing concrete walls to support and reinforce cave walls, and a dike system surrounding the base of the island cluster to help handle the stability of the base of Hon Trong Mai.

Before analyzing and evaluating the social factors affecting the landslides, landslides and erosion of Trong Mai island, the authors studied the relationship between the number, speed, and distance of ships and their impacts on the stability of Trong Mai island, thereby suggesting some social and engineering solutions to minimize the impact on the stability of Trong Mai island.

At the workshop, experts from the Norwegian Geotechnical Institute, Dr. Rainder Kumar and Dr. LLoyd Warren, analyzed the rock mechanical properties related to the stability of Trong Mai Islet, compared them with natural heritages in the world that have been preserved by the Norwegian Geotechnical Institute's experts, and from there, made comments and proposed solutions to stabilize Trong Mai Islet in Ha Long Bay.

Some initial experimental studies have also been conducted by Norwegian experts in collaboration with the Institute of Geosciences and Mineral Resources in Ha Long Bay recently.

The Norwegian experts' proposals have some points that are not similar to the proposal of the Institute of Water Resources, such as the conservation plan without changing the landscape and only having the smallest impact to ensure the stability of Hon Trong Mai over time.

Source link: https://thanhnien.vn/chuyen-gia-noi-gi-ve-nguy-co-sat-lo-hon-trong-mai-tren-vinh-ha-long-185230731202634759.htm