CN108824365B

CN108824365B - Double-deck arc riverbed ecological remediation structure

Info

Publication number: CN108824365B
Application number: CN201810677682.8A
Authority: CN
Inventors: 陈孝兵; 袁越
Original assignee: Hohai University HHU
Current assignee: Hohai University HHU
Priority date: 2018-06-27
Filing date: 2018-06-27
Publication date: 2020-07-14
Anticipated expiration: 2038-06-27
Also published as: CN108824365A

Abstract

The invention discloses a double-layer arc-shaped riverbed ecological restoration structure which comprises an outer-layer overflow weir, an inner-layer overflow weir and a rock dam abutment, wherein the inner-layer overflow weir and the outer-layer overflow weir are both arc-shaped and protrude towards the upstream of a river, the inner-layer overflow weir is arranged at the downstream of the outer-layer overflow weir, the two layers of overflow weirs are both low in the middle and high in two sides and are connected with the rock dam abutment. Compared with the existing river channel protection measures, the river channel protection device has multiple functions of protecting river bank erosion, enhancing surface water and underground water exchange, protecting a river channel ecological system, enhancing the self-purification capability of the river channel and the like. This structure has not only avoided the destruction to river course ecosystem, has strengthened the connectivity that has strengthened surface water groundwater on the contrary, can effectively protect natural river course ecosystem, strengthens river course water self-purification ability, provides the habitat for aquatic organisms simultaneously. The invention has low cost, less manpower and long structural life, and has wide application prospect in the fields of river regulation, river bank protection, river water pollution control and the like.

Description

Double-deck arc riverbed ecological remediation structure

Technical Field

The invention relates to the field of river water and soil conservation and river ecological management, in particular to a double-layer arc-shaped riverbed ecological restoration structure and a design method.

Background

Water and soil conservation is a life line for mountain development, is the basis of land reclamation and river management, and is the basis of national economy and social development. River bank erosion exists in almost all river coasts, the eroded river banks often cause serious environmental problems, and river bank collapse with high strength even causes great danger, and the life and property safety of people along the coasts is seriously threatened. The silt stripped from the river bank can further destroy the water quality after entering the river, influence the growth and development of aquatic organisms, even deposit in a downstream river channel, and influence navigation. The traditional river regulation measures such as straightening, hardening and the like can cut off the communication relationship between the underground water body in the river bed substrate and the surface water body in the river, so that the contact between animals, plants and microorganisms in the river bed water body and the river bed substrate is cut off, the living environment is deteriorated, and the natural self-purification capability of the river is reduced. In addition, with the rapid development of economic society in recent years, human factors are destroyed, river pollution is increasingly serious, and seasonal or perennial black and odorous water bodies are becoming water environment problems to be solved urgently in river ecological treatment in China.

At present, the technology adopted by China in the fields of river bank erosion prevention, river ecology maintenance, river pollution treatment and the like basically stays in the aspect of separately treating surface water, but the surface water and underground water are not considered as an organic whole, and the stronger connectivity exists, so that the significance of the mutual exchange of the surface water and the underground water on a river ecological system is ignored. The region where river water and surface water are crossed, namely the undercurrent zone, is a region for exchanging substances and energy and growing and breeding biological communities, and plays an important role of 'river liver' in the aspect of maintaining the ecological health of rivers. A large number of researches show that the undercurrent belt has important significance in promoting nutrient substance circulation, relieving polluted water, providing and maintaining good aquatic organism habitat and the like.

Therefore, in river regulation, an ecological restoration means capable of preventing river bank erosion without hardening the river and comprehensively considering the process of surface water and underground water so as to enhance the self-purification capability of the river is urgently needed.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a double-layer arc-shaped riverbed ecological restoration structure, which can protect a river bank from erosion, prevent ecological damage caused by hardening a riverway and enhance the self-purification capacity of the river by increasing the surface water and underground water exchange so as to control the river pollution.

The technical scheme is as follows: double-deck arc riverbed ecological remediation structure, including outer weir, inlayer weir and rock block dam abutment, inlayer weir and outer weir all are the arc and bulge to river upper reaches, and the inlayer weir is in outer weir low reaches, and two-layer weir all middle low both sides height to link to each other with the rock block dam abutment.

The length of the outer overflow weir is 2-3 times of the width of the river, and the included angle between the two sides of the outer overflow weir and the river bank is 20-30 degrees.

The restoration structures are continuously arranged in the riverway at proper intervals, so that the undercurrent exchange effect between surface water and underground water is enhanced on a large scale, and the ecological restoration of the watershed scale is realized.

The outer layer overflow weir is formed by inlaying different-diameter stones, and the inner layer overflow weir is formed by inlaying equal-diameter stones.

The rock block dam abutment vertically extends into the river bank and forms an included angle of 110-120 degrees with two arms of the arc-shaped structure of the outer layer overflow weir.

The overflow weir raises the upstream water level, and a scouring pit is formed below the overflow weir, so that a pressure gradient is formed on the riverbed, and the vertical surface water and underground water exchange process is enhanced.

The working principle is as follows: the river channel adopts a structure that the double-layer overflow weirs are arranged on the rock blocks, the middle of the river channel is low, and the two sides of the river channel are high, so that water flow intensively overflows from the middle of the river channel, the water flow speed at the two sides of the river channel is reduced, and the shear stress at the river bank is reduced, so that the river bank is protected from water flow erosion. The double-layer arc structure shares the river water energy dissipation process, reduces the undercut erosion of the river channel, and simultaneously makes a pressure gradient on the riverbed to enhance the surface water and underground water exchange process.

The overflow weir comprises an inner arc-shaped rock block overflow weir and an outer arc-shaped rock block overflow weir and a dam abutment, and the upstream bulge of the overflow weir structure is arc-shaped, so that force is effectively transmitted to the dam abutment, and the overflow weir is prevented from being damaged by scouring when water flow is large. The middle of the overflow weir is low, and the two sides of the overflow weir are high, so that the river water flows in a concentrated manner from the middle of the overflow weir, the flow rate in the middle of the river is increased, and the flow rates on the two sides of the river are reduced, thereby reducing the shear stress at the river bank and preventing the sediment at the river bank from being degraded by water flow. When the river course was arranged, this structure wholly stridees across the river course symmetrical arrangement, and the dam abutment side direction stretches into the river bank, and the protruding department of structure is the direction of meeting water, and rivers can be cut down behind the overflow weir and produce the scouring pit of two different degree of depth and scope, form the pressure gradient of echelonment on the both sides riverbed of double-deck overflow weir simultaneously, have promoted vertical surface water groundwater exchange. The double-layer overflow weir raises the upstream water level, slows down the upstream river channel specific drop, delays erosion, and simultaneously, the flow velocity in the middle of the river is fast, and silt is taken away to prevent siltation. The double-layer arc-shaped overflow weir structure shares kinetic energy generated by water head reduction, undercutting erosion at the downstream of the weir is reduced, and meanwhile, pressure gradient is formed on a riverbed by water level difference between the upstream and the downstream of the weir. Surface water enters the underground water body in an area with high upstream pressure and returns to the river channel in an area with low downstream pressure, so that the structure can greatly enhance the exchange process of the surface water and the underground water in the river channel system. A large amount of dissolved oxygen, nutrient substances and pollutants enter the river bed bottom material along with surface water, a large amount of complex physical, chemical and biological processes occur under the catalysis of microorganisms of the river bed bottom material, the migration and conversion process of nutrient substances such as carbon, nitrogen and the like and the decomposition process of the pollutants are completed, and the purification of the water quality of the river is realized. The upper stream flow velocity of both sides of the weir is slower, which provides a good habitat for the survival, propagation and refuge of aquatic organisms, and the middle part of the weir is lower, which does not influence the free migration of the aquatic organisms in the upper stream and the lower stream.

Has the advantages that: compared with the prior art, the invention has the following advantages: (1) the river channel protection device can effectively protect the two banks of the river channel at the upstream and downstream positions of the structure and prevent the erosion of silt and the collapse of the river bank caused by the erosion of the river channel. (2) The method disclosed by the invention not only avoids ecological damage caused by the traditional method for hardening the riverway to crack the surface water underground water system, but also enhances the connectivity of the surface water underground water, can effectively protect the natural riverway ecological system, enhances the self-cleaning capability of the riverway and relieves the water pollution. (3) The invention can provide a good habitat for the survival, propagation and refuge of aquatic organisms, and further protect the river channel ecosystem. (4) The material of the invention is only the rock block, which is convenient for local material construction, the arrangement is less limited by the region condition, the cost is low, the construction speed is high, the required maintenance is less, and the structure life is long.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic cross-sectional view of the present invention;

fig. 3 is a diagram of a watershed scale arrangement of the present invention.

Detailed Description

As shown in fig. 1 and 2, the double-layer arc riverbed ecological restoration structure comprises 3 parts, namely an outer-layer overflow weir, an inner-layer overflow weir and a rock dam abutment 4. The outer overflow weir is arc-shaped and protrudes towards the upstream of the river, the whole length is 2-3 times of the width of the river, and the included angle between the two sides of the outer overflow weir and the river bank is 20-30 degrees. The outer layer overflow weir is formed by inlaying the stones with different diameters against the water flow direction, wherein the diameter of the small-diameter stone 2 is 30cm, the stone is arranged in the water flow direction, and the stone is inlaid in a gap of the large-diameter stone 1 with the diameter of 50 cm. The middle of the overflow weir is short and has two high sides, the lowest height of the arc top is 1/2 of the common water level of the riverway, the two sides of the overflow weir are gradually increased, and the weir height of the overflow weir at the position close to the dam abutment 4 is slightly lower than the common water level of the riverway. The inlayer overflow weir arranges outer overflow weir low reaches, and two weir arc tops department are inlayed for 1/3 of river width length apart from the lump stone 3 that is 40cm by the diameter and form, and the short both sides height in the middle of is the same, and the high minimum of arc top is 1/3 of the common water level of river course, and both sides increase gradually, and the control weir height is less than the common water level of river course a bit near dam abutment 4 department. The two layers of overflow weirs are connected with the dam abutment 4, the dam abutment 4 is composed of stones with the diameter of 60cm to 100cm, the stones vertically extend into the river bank, and the included angle between the two arms of the arc-shaped structure of the outer layer of overflow weir is 110-120 degrees. Under the action of water flow scouring, a scouring pit 5 is formed between the two overflow weirs, a scouring pit 6 is also formed at the downstream of the inner overflow weir, and a pressure gradient is formed on the riverbed, so that vertical surface water firstly enters along a subsurface flow exchange path 7 and then leaves the bottom materials of the riverbed.

As shown in figure 3, the structures of the invention are continuously arranged in the river channel at proper intervals, so that the subsurface flow exchange effect between surface water and underground water can be enhanced on a large scale, and the ecological restoration of the river basin scale is realized. The arc-shaped structure can transmit force generated by water flow scouring to the dam abutment, and the dam abutment extends into a river bank, so that the water flow scouring resistance is enhanced, and the stability of the structure is maintained.

Claims

1. The utility model provides a double-deck arc riverbed ecological remediation structure which characterized in that: the dam comprises an outer-layer overflow weir, an inner-layer overflow weir and a rock dam abutment, wherein the inner-layer overflow weir and the outer-layer overflow weir are both arc-shaped and protrude towards the upstream of a river, the inner-layer overflow weir is arranged at the downstream of the outer-layer overflow weir, and the two layers of overflow weirs are both low in the middle and high in two sides and are connected with the rock dam abutment;

the length of the outer-layer overflow weir is 2-3 times of the width of the river, and the included angle between the two sides of the outer-layer overflow weir and the river bank is 20-30 degrees;

the restoration structures are continuously arranged in the riverway at proper intervals, so that the undercurrent exchange effect between surface water and underground water is enhanced on a large scale, and ecological restoration of the watershed scale is realized;

the outer-layer overflow weir is formed by inlaying different-diameter stones, and the inner-layer overflow weir is formed by inlaying equal-diameter stones;

the block stone dam abutment vertically extends into the river bank, and the included angle between the block stone dam abutment and two arms of the arc-shaped structure of the outer layer overflow weir is 110-120 degrees;

the upper water level is raised by the outer layer overflow weir and the inner layer overflow weir, and a scouring pit is formed under the overflow weir, so that a pressure gradient is formed on a riverbed, and the vertical surface water and underground water exchange process is enhanced.