Study On The Hydraulic Characteristics And Regulation Measures Of The Deepwater Rapids Of Shui Tianjiao

The navigation condition of the river between the two Dams is extremelydangerous because of its steep vally wall, narrow and deep channel, rapid flow,inordinate water state and concentrated navigation-hampering shoals. Shui Tianjiao isthe famous flood rapids in Yangtze river, and it is also one of the most difficultnavigation segment between the two Dams. To ensure the unimpeded transportation ofthe “golden waterway” and to improve the ability of navigation, it is of great importanceto study the flow characteristics and the regulation measures of Shui Tianjiao.With the two-dimensional flow simulation technology, this paper preliminarilystudies the flow characteristics and the regulation measures of Shui Tianjiao, the maincontents and results are as follows:(1)To carefully validate the two-dimensional flow mathematical model with theconcrete hydrological data of Liantuo, to get the right calculation parameters such asroughness and mesh density to better simulate the flow field.(2)To use the two-dimensional flow mathematical model to calculate the flow fieldof Liantuo under several levels of flood flow, to analyze of its flow condition in detail.The results show that Shui Tianjiao is bedrock flood rapids whose main flow conditionis rapid flow. The valley is narrow, river width is from tapering to sudden expansion, thegrowth rate of discharge and cross section area is unbalanced, velocity distribution isuniform laterally. These are the main causes of shoal formation.(3)To study the measure of enlarging discharge area by different excavation, itshows that the regulation effect on steep and deep-water rapids is not obvious only byexcavation to expand discharge area. It’s difficult to reach the remediation goal.(4)To propose an unconventional rapids method based on the flow condition ofsmall velocity in shallow water. That is to build submerged dam to create slow flow area.To calculate the tests combined with different parameters of submerged dams. Theresults show that relying solely on this method is hard to significantly improve flowcondition. The regulation effect is only slightly better than the expansion of dischargearea.(5)To put forward the comprehensive method of “left dredge and right raise” basedon the two regulation measures mentioned above. That is to expand discharge area onleft side and to build submerged dam on the opposite to reduce the water depth and form slow flow channel. It can obviously improve the water condition of rapids and enhancethe navigation flow. It basically achieves the remediation goal.(6) Finally, to analyze the applicable condition of the method-“left dredge andright raise”. It only applies to the deepwater reservoir rapids, which the flow is fast, theflow condition on two sides is conducive to “take jump”, the water level during floodingand drying changes slightly.