The emergency at Tuanzhou polder in Huarong County, Dongting Lake, has touched the hearts of people across the nation. The Hunan Provincial Party Committee deployed emergency measures at the first opportunity, carrying out rescue and emergency response in parallel, thereby minimizing more severe losses to people's lives and property. However, the question of which construction methods and equipment should be adopted for repair and treatment projects similar to the cofferdams of the Dongting Lake water network infrastructure, so as to better ensure the long-term safety of dikes and dams, has also drawn greater attention and reflection from industry professionals.

There are many methods and types of equipment for seepage prevention and reinforcement construction of cofferdams in rivers, lakes, and reservoirs in plain areas. The commonly used ones are as follows: first, using hydraulic diaphragm wall grabs to form trenches and then pouring concrete for seepage prevention and reinforcement; second, using high-pressure jet grouting reinforcement supplemented with polyethylene geomembrane for seepage prevention; third, using the CSM deep mixing method to mix a certain proportion of concrete with the original dam foundation soil to form a wall, completing seepage prevention and reinforcement in one operation; fourth, the TRD method, which is similar to the CSM deep mixing method and can also achieve integrated seepage prevention and reinforcement. Each of these methods has its own merits. The selection of construction method and equipment must take into account not only the applicability requirements of equipment under project conditions and geological conditions, but also construction efficiency and economy. The table below compares several commonly used methods and equipment for dam seepage prevention and reinforcement:

Shanghai Jintai's CSM construction method products emerged in response to the 2010 South-to-North Water Diversion Xinglong Reservoir project. Since then, their application has been continuously expanded across China in fields such as reservoir cofferdam risk elimination and reinforcement, underground pollution remediation, urban foundation pit waterproof curtains, and trench wall reinforcement for large bridge anchorage foundation pits. In 2018, the technology won the second prize of the National Science and Technology Progress Award (this construction method and equipment technology solved the difficult problem of deep groundwater control faced by deep and large underground space development under complex geological and urban sensitive environmental conditions, and is applicable to engineering fields such as water conservancy project seepage prevention, landfill pollutant isolation, and deep soft soil foundation treatment; its main achievements have reached the international leading level — evaluation report of candidate projects for the National Science and Technology Progress Award). In 2023, it was included in the Ministry of Water Resources' "2023 Key Promotion Guidance Catalog of Advanced and Practical Water Conservancy Technologies" and was recognized by the Ministry of Water Resources as advanced and practical water conservancy technology.

Xinglong Water Conservancy Project of the South-to-North Water Diversion

Hainan Wenchang - Zhongnan Reservoir Emergency Reinforcement Project, Dongting Lake Cofferdam

Yellow River-to-East Water Diversion (Dongying Section)

Boxing Water Conservancy Project, Shandong

Xinier Reservoir Dam Foundation Seepage Prevention and Reinforcement Project, Xinjiang

Rizhao Shanhaitian Tourist Resort Underground Reservoir, Yellow River-to-East Water Diversion

Dongting Lake Changchun Polder Dike Reinforcement Project