US-12624509-B2 - Method for regulating confluence of tributaries with large drop difference and large angle into trunk canal

US12624509B2US 12624509 B2US12624509 B2US 12624509B2US-12624509-B2

Abstract

Disclosed is a method for regulating confluence of tributaries with a large drop difference and a large angle into a trunk canal. The method includes: banking up a reservoir at an upstream end of a tributary river, and widening a water surface, such that uniform distribution of water flows is completed; then conducting scouring and energy dissipation to reduce a flow velocity and kinetic energy of the water flows; then conducting flow-slowing sedimentation, such that sediment is deposited on one side of the tributary river connected to a downstream side of a trunk stream; and then conducting flow diversion at one side of the tributary river connected to an upstream side of the trunk stream, such that an included angle of confluence of tributary river water into the trunk stream is reduced.

Inventors

Yunli WANG
Shiliang ZHOU
Chunhao YAN
Meitao XIANG
Xiaorong Wang
Xiaoyi Wang
Jilun MIAO
Shengfa YANG
Tao Yu

Assignees

CHONGQING JIAOTONG UNIVERSITY

Dates

Publication Date: 20260512
Application Date: 20240509

Claims (8)

1 . A method for regulating confluence of tributaries with a large drop difference and a large angle into a trunk canal, comprising: banking up a water level at an upstream end of a tributary river, and widening a water surface, such that uniform distribution of water flows is completed; then conducting souring and energy dissipation to reduce a flow velocity and kinetic energy of the water flows; then conducting flow-slowing sedimentation, such that sediment is deposited on one side of the tributary river connected to a downstream side of a trunk stream; and then conducting flow diversion at one side of the tributary river connected to an upstream side of the trunk stream, such that an included angle of confluence of tributary river water into the trunk stream is reduced; wherein the method is implemented by means of a hydraulic construction system for energy dissipation, sediment settling and flow diversion of a tributary river, wherein the hydraulic construction system for energy dissipation, sediment settling and flow diversion of a tributary river is arranged in the tributary river and comprises a high platform, a stilling basin, a low platform and a diversion dike that are sequentially connected from the upstream end to a upstream section of the tributary river, wherein an upstream end of the high platform is provided with a sediment-blocking downflow weir, riverbanks on two sides of the high platform are designed to be splayed and widened in a downstream direction, a downstream end of the high platform is connected to a steep slope of the stilling basin, a lower end of the steep slope is connected to a basin body of the stilling basin, a downstream end of the basin body of the stilling basin is connected to the low platform, an upstream end of the low platform is higher than a bottom of the basin body of the stilling basin such that the basin body is formed, the diversion dike has a consistent water flow direction with the trunk stream of a confluence and is fixedly arranged at a joint of an upstream side of a tributary and the trunk stream such that the diversion dike and the upstream side of the tributary river intersect at an obtuse angle, and a lower half of the low platform is located between the diversion dike and an opposite tributary downstream side bank; and wherein a trunk river has a widening zone formed through external widening on upstream and downstream sides of the confluence of the tributary, the tributary is connected to the widening zone, and the diversion dike is arranged in the widening zone.
2 . The method for regulating confluence of tributaries with a large drop difference and a large angle into a trunk canal according to claim 1 , wherein through banking-up of a reservoir at an upper end of the tributary river, bed load sediment in the tributary river is settled before the water surface is widened; and then, suspended load sediment in the tributary river is settled after scouring and energy dissipation are conducted on the water flows.
3 . The method for regulating confluence of tributaries with a large drop difference and a large angle into a trunk canal according to claim 1 , wherein the steep slope of the stilling basin has a slope of 1:4; and the basin body of the stilling basin has a length of 30 m-50 m and a depth is 1 m-2 m.
4 . The method for regulating confluence of tributaries with a large drop difference and a large angle into a trunk canal according to claim 1 , wherein a widened joint section is excavated on a bank of the trunk canal at a joint below a confluence of the trunk stream and the tributary in an expanded manner.
5 . The method for regulating confluence of tributaries with a large drop difference and a large angle into a trunk canal according to claim 1 , wherein a bank of one side, corresponding to the diversion dike, of the low platform is provided with a concave arc-shaped downstream settlement zone.
6 . The method for regulating confluence of tributaries with a large drop difference and a large angle into a trunk canal according to claim 1 , wherein the sediment-blocking downflow weir comprises a middle weir arranged along a cross section of the tributary river, and further comprises an upper weir arranged on an upstream side of the middle weir in a spaced manner, and cross sections of the upper weir and the middle weir are both convex arc-shaped.
7 . The method for regulating confluence of tributaries with a large drop difference and a large angle into a trunk canal according to claim 6 , wherein the upper weir is obliquely arranged in an upstream direction of the tributary at one end of a bank where the diversion dike of the tributary is located.
8 . The method for regulating confluence of tributaries with a large drop difference and a large angle into a trunk canal according to claim 7 , wherein an upstream side of the upper weir is provided with a concave arc-shaped upstream settlement zone on a bank of the tributary facing away from the diversion dike; a bottom of the concave arc-shaped upstream settlement zone is provided with a sediment discharge pipe, a lower end of the sediment discharge pipe is obliquely downward connected to a bank of the concave arc-shaped downstream settlement zone so as to form a sediment discharge port, an upper end port of the sediment discharge pipe is provided with a sediment discharge valve, and a stirring device is mounted outside the sediment discharge valve; and the sediment-blocking downflow weir further comprises a lower weir arranged on a downstream side of the middle weir in a spaced manner, and a cross section of the lower weir is convex arc-shaped.

Description

TECHNICAL FIELD The disclosure relates to the technical field of canal navigation safety maintenance, and particularly relates to a method for regulating confluence of tributaries with a large drop difference and a large angle into a trunk canal. BACKGROUND A canal refers to a man-made navigable river. China's Ministry of Transport has taken great efforts to increase investments in water transport infrastructure recently. Some major national strategic projects have been successively started, such as the Yangtze River diversion project to feed the Huaihe River and the backbone project of the new western land-sea passage-Pinglu Canal. A new canal has a long line, and needs to cross many small and medium-sized natural rivers through dredging and excavation. The canal has a large number of confluences of a trunk stream and tributaries (the Yangtze River diversion project to feed the Huaihe River involves 156 confluences and the Pinglu canal has 27 confluences). The trunk stream and the tributaries of the canal have complicated water conditions, which generally require special regulation. Considering that the canal needs to be designed to have its own smooth river, the water level difference of the canal cannot be excessively large, and otherwise a large elevation difference between tributaries and a riverbed of a trunk canal will be caused. At present, a maximum elevation difference between tributaries and a trunk stream of the Pinglu canal is up to 14.7 m. In addition, since the canal is excavated manually, it generally has to be initiatively connected to tributaries during its route planning, and there are limitations of boundary lines of land for canal excavation. Therefore, a sharp-bend river is likely to be formed at a confluence of a riverbed of a trunk stream and a tributary, and the tributary can be connected to a trunk river from a concave bank side of a canal bend. In this way, confluence angles between all tributaries and a trunk canal are mostly large, the maximum one of which is 90°. Therefore, large-drop-difference confluence and sharp-bend confluence frequently occur at a confluence of a trunk canal and tributaries. In this way, a transverse flow velocity of water flows in a channel at a confluence of the canal will be large after tributary confluence. Meanwhile, due to circulation flows of a sharp-bend river, a water flow structure at a confluence of a trunk stream and tributaries is very complicated, with a chaotic flow condition. Moreover, if tributary sediment flows into the trunk canal, a channel size can be obviously reduced, which will cause a water surface of the confluence to fluctuate greatly. All kinds of factors can seriously affect navigation of ships. However, the river confluence is originally a place that is very conducive to biological reproduction and growth in river water because of its rich oxygen content and organic matter content in water. The canal's ecological environment is relatively poor through manual excavation, so it is necessary to improve construction of a river ecosystem by relying on beneficial conditions of a tributary confluence. However, excessively large flow impact, excessively chaotic flow conditions and serious sediment scouring and siltation at a confluence of a trunk stream and a tributary can greatly destroy ecological functions of the confluence of the canal and are not conducive to improvement in an ecological environment of the canal. According to experience and practice, generally in a case that a drop difference of a tributary at a confluence is larger than 5 m and meanwhile an included angle of an upstream side of the confluence between the tributary and a trunk stream is larger than 30° due to a sharp bend of the trunk stream, special regulation needs to be conducted on the tributary, so as to better ensure navigation stability and maintain ecological functions of the canal confluence. In the Yangtze River diversion project to feed the Huaihe River currently under construction, if a tributary mouth and a trunk canal are not properly regulated, a canal channel size will be greatly influenced, development of a new large-sized canal shipping project will be seriously affected, and maintenance cost of the canal will be greatly increased. At present, the Pinglu canal, with a total length of 135 km, is in a design and construction stage. It is critical to focus on navigation, sediment blocking and comprehensive management of an ecological environment at a confluence of a trunk stream and tributaries so as to implement canal construction and give full play to canal functions. Therefore, it is necessary to propose a regulation method that integrates navigation, sediment blocking and ecological management at a confluence of a trunk stream and each tributary, so as to solve problems of navigation flow conditions, sediment deposition, and river biological growth. SUMMARY In order to overcome the defects in the prior art, a technical problem of the disclosur