Applied Research Of Submerged Dam On Torrent Rapids Regulation Of Lancang River

From the Jinghong to the 244 boundary pillars of the Lancang River,there are many beach risks,often accompanied by acute,shallow and uninhibited navigation phenomena.With the development of shipping,the grade of the channel is required to be upgraded from the original five levels to the fourth level channel,and the navigational ship is 300 t.Increased to 500 t level,the requirements of navigation standards are higher,further improving the difficulty of rectification of the Minjiang River rapids.The fundamental method of shoal remediation is to expand the drainage area method.The main problem brought by this measure is the drop of the water level.In order to reduce the water level drop,the dam sluice measures are often adopted;the low water flow is small,and the water needs to be taken into consideration.The navigation depth at the submerged dam often limits the layout conditions of the submerged dam.In addition,due to the steep flow of the Suijiang River,it is difficult to construct the riprap on the water.In the past practice,the dam was less adopted.The paper mainly uses the generalized water tank test and the physical model test research of the engineering section to study the hydrophobic characteristics of the submerged dam suitable for the remediation of the Lancang River,the layout of the submerged dam and the structure type,and summarize the differences of the submerged dam in the Lancang River and the Shoal.The remediation plan,the main work content and research results are:(1)In the generalized topography of the Shunzhi River section,the hydraulic characteristics of the single submerged dam and the double submerged dam under different working conditions are analyzed and compared,and the rationality of the water level of the single submersible dam is verified.The dam has carried out the corresponding calculation of the drowning water.When the effect of the single submerged dam is insufficient,the way of arranging the double dive dam can be selected.In order to meet the requirements of the submarine dams required by the Lancang River,it is recommended to be suitable for the submerged dam height of some of the reclamation needs of the Lancang River.(2)According to the problem that the over-water area of the submerged dam is effectively intercepted by the submerged dam of the shoal and trough,the problem of poor drowning is analyzed.The hydraulic characteristics of the submerged dam and the filling sluice of different heights are analyzed and summarized.The relationship between the height of the drowning water and the blocking area is based on the scale and economic problems of the actual project.(3)In view of the “shallow” characteristics of some beach sections of the Lancang River,the location of the downstream of the inter-strait topography is selected by the filling arrangement.The experimental results show that the filling tank changes the bottom elevation of the riverbed and raises the height of the downstream riverbed.The overall water level rises,and the location,width,length and other factors of the filling will affect the effect of drowning.(4)In the physical model test of the Lancang Hekuan Beach,the hydraulic characteristics of the submerged dam and the filling trough were systematically analyzed.Then,according to the calculation of the ship's sinking amount,the height of the sink in the straight section was summarized.After the water-repellent mechanism of the submerged dam and the water-blocking mechanism of the submerged dam between the shoal and the shoal,it can be seen that the drowning effect is obvious when the underwater-4m submerged dam is arranged,but according to the actual remediation requirements and construction difficulty,by improving the structural type of the submerged dam,The underwater-6m Ding dam was applied in the actual renovation plan of Hekuantan,and the treatment effect was analyzed.Finally,the effects of different types of slums on other shoals and shoals in the Minjiang River were summarized.