Sluice gate uses and types
The sluice gate is one of the main buildings in water conservancy projects such as irrigation and waterlogging. It is mainly: the function of controlling the flow scene and adjusting the water level through sluice gate hoist.
1. Classified according to the purpose of the sluice gate
1) Intake sluice gate
Built on the banks of rivers, reservoirs, or lakes, and at the head of irrigation diversion channels, to ensure and control the flow into the canal. Since the inlet gate is located at the head of the canal, it is also called the headgate.
2) Divide sluice gate
The sluice gate is used to introduce the flow of the upper-level channel into the next-level channel as needed. In fact, it is the inlet gate of the next-level channel. The water distribution building in the department. Due to the different locations of the diversion gates, it is customary to have different names. For example, the head of the branch canal is called the branch canal inlet; the inlet of the canal, agricultural canal, and other channels is called the Doumen, Nongmen, etc.
3) Control sluice gate
Control gates are generally built across the trunk and branch canals and are located downstream of the branch and bucket canals to control the water level in front of the sluice and meet the water level requirements of the branch and bucket channels. The control gate mainly uses the opening and closing of the gate to control the water level of the channel. In the canal section that uses the canal drop to generate electricity, the flow can be adjusted by the control gate. When the control gate and the discharge gate are built together, the water flow can be controlled to ensure the discharge, so as to achieve the purpose of jointly ensuring the safety of important canal sections or buildings. Therefore, the control gate is a control building that controls the water level, regulates the flow, and ensures the distribution and discharge of water.
In order to do a good job in planning water use, allocate water reasonably, and further save water resources, sluices in irrigation districts should have the function of measuring water in addition to the above-mentioned respective functions.
4) Sluicing gate
Sluice gates are generally built-in important canal sections (such as large fills, high slopes, and canal sections with poor geological conditions) or important canal structures (such as aqueducts, inverted siphons, tunnels, and water distribution hubs, and other key buildings) On the upstream side of the canal, there is a short discharge canal line behind the sluice (river, ravine, etc. should be used as much as possible) to discharge the water into the discharge area. When flooding occurs downstream, endangering the safety of buildings, or when an accident occurs in a dangerous construction site and needs to be repaired, the sluice gate can drain the flood or canal water in time to ensure the safety of important canal sections or key buildings. When the sluice gate is installed at the end of the irrigation channel, it is used to drain the remaining water in the canal, also known as the sluice gate. In the project, the sluice gate is also installed downstream of the canal system into which the slope water or ground runoff is injected, so as to pass the sluice gate Eliminate runoff in time.
5) Drain sluice gate
Drainage sluice gates are built at the end of drainage channels to discharge floodwater in the controlled area into rivers or lakes to prevent waterlogging. Sluice drains; when the control area has the task of water storage and irrigation, the sluice gate can be closed to store water when the water level of the outer river is low. In addition to the functions of blocking tides and draining waterlogging, the drainage gates built in the tidal section can also draw the river water (freshwater) supported by the high tide during the water demand period of the control area for irrigation. During the low tide, the ship was opened to facilitate shipping.
The characteristic of the drainage sluice gate is that it not only needs to hold the water in both directions but also can pass the water in both directions.
6) Rinse sand sluice gate
Sand flushing sluices are mostly built at the end of sedimentation basins in diversion hubs or canal systems on sediment-laden rivers, also known as sand sluices. When there is sediment deposition in front of the gate, the sluice gate can be opened to release the water, and the sediment deposited in the upstream river section or canal section can be washed away by the water. The sand flushing gates in the canal system can also be set up at the water diversion junctions with control sluice gates, or the sluice gates can be used to discharge sand.
2. Classified according to the structure of the sluice chamber
1. Open sluice
There is no soil filling on the open sluice chamber (Figure 1-1).
It is a structural type widely used in sluices. This type is generally used when the water level in front of the canal headgate, control gate, and drainage gate does not change much. Open sluices are often used when the dikes are not high and the diversion flow is large. Open sluices include two types: those with parapets (Figure 1-2) and those without parapets. When the upstream water level varies greatly, and the flow through the sluice is not large, it is stated in the “Sluice Design Code” SD133-84 The retaining water level of the sluice is higher than the water level used for the discharge. For example, the headgate of the canal often adopts the parapet sluice. The height of the gate of the parapet sluice has been reduced, which also reduces the height of the working bridge and reduces the opening force of the gate. For sluices with a higher parapet wall and lower anti-sliding stability of the gate chamber, a section of the gate chamber behind the parapet wall can be made closed, that is, the top part of the gate can be filled, and the filling is used to increase the anti-sliding stability of the gate chamber. . At this time, the parapet wall also functions as a retaining wall, and the pavement on the top of the fill can meet the traffic requirements. The lock chamber of this arrangement can be called a semi-closed lock chamber (Figure 1-3), but its working characteristics and design methods are the same as those of the open water rigid lock chamber. It should be emphasized that the semi-closed lock chamber The sluice not only uses the soil weight to increase the stability of the sluice chamber, but also requires the foundation to have a higher bearing capacity, and the length of the sluice chamber is relatively enlarged.
2) Culvert sluice gate
Culvert sluices gates are mainly built on channels with high dikes and small diversion flows. Filling soil on the cave body as a roadbed, the structure of the connecting buildings on both sides of the bank is much simpler than that of an open sluice, so it is often more economical. According to different hydraulic working conditions, culvert sluices can be divided into two types: pressure culvert and non-pressure culvert (Figure 1-4). In irrigation and drainage projects, small drainage sluices and discharge sluices (and sand sluices) are often used. Pressure-type small sluice gates such as buckets and agricultural gates are often pressure-free. The culvert inlet gate is composed of three parts: the entrance header, the tunnel body, and the entrance and exit connecting section. The culvert sluice is equipped with penstock at the entrance, and corresponding opening and closing equipment are arranged to form the entrance head. This is the difference between it and the culvert. But in terms of working characteristics and design methods of the cave body, it is basically the same as the culvert.
Culvert sluices have the following characteristics:
①Mainly rely on the filling of the cave body to keep water;
②The flow pattern in the cave body changes with the change of the water level in front of the sluice. Different flow patterns such as pressure-flow;
③The anti-seepage of the gate foundation and the anti-seepage of the embankment are considered together;
④The height of the filling of the tunnel body is different, and the load is unevenly distributed along the tunnel body.
The tunnel body should be appropriately segmented, and settlement joints and stop Water equipment to prevent uneven settlement and endanger the safety of the cave. For this reason, when designing:
① Strive to only appear in one flow pattern. For unpressurized culvert sluices located on sediment-laden rivers, the bottom slope of the cave body should be appropriately enlarged to prevent sedimentation and siltation;
②The quality of the joints should be paid attention to, and water stop facilities should be made to prevent water leakage: set along the outside of the cave body Cut-off ring or anti-seepage tooth wall to prevent contact and erosion.
③The gap between the joints should be appropriately shortened, and the longitudinal reinforcement of the hole should be strengthened;
④The settlement in the middle of the hole is large, and the settlement at both ends is small. According to the settlement calculation results, the bottom elevation of the middle section of the hole should be appropriately increased, even The middle part of the axis is arched upwards.
Sluice gate location selection
The selection of the sluice gate site should be based on the characteristics and application requirements of the sluice, comprehensively considering the topography, geology, water flow, sediment content, construction and management, and other factors, and determined after comparing the schemes.
1. Factors to be considered when choosing sluice gate location
1) Geological conditions
The sluice gate site should be chosen as far as possible on a natural foundation with uniform and compact soil quality and low compressibility, and artificial foundation treatment should be avoided. Since the level of groundwater and the presence of confined water also affect the construction drainage measures and the stability of the foundation, these conditions should be considered when selecting the gate site. The condition of the foundation soil must be clarified, not subjectively judged, and not comprehensive. To do sufficient investigation and research and necessary exploration tests, we must never draw conclusions after drilling a hole or digging a pit. More attention should be paid to important culverts and sluice gates or areas with more complicated soil quality changes (such as river network areas, riverbanks, and lakes, etc.). A certain number of boreholes (or test pits) must be drilled according to the design requirements, and sufficient foundation soil information can be guaranteed. There are many lessons for building accidents due to poor foundation conditions and insufficient prior knowledge. For example, a culvert was built on a flattened river slope. Half of the foundation is hard soil and half is silt soil. After completion, Soon, the cave body broke. After drilling several holes on the right side of the axis of a single-hole gate, it was found that the quality of the silt soil was good, so the left side soil was subjectively considered to be the same, and no hole drilling was provided. After the sluice pond was excavated, it was discovered that a mud pond was not too deep under the topsoil on the left, and the silt was very deep, which seriously affected the layout and construction of the bank and wing walls.
2) Water flow conditions
The location of the sluice gate should make the incoming and outgoing water flow more uniform and smooth, and there should be better straight river (canal) sections before and after the gate. The sluice gate site should be selected to avoid the places where harmful erosion and sedimentation may occur upstream and downstream.
3) Construction and management conditions
There should be good construction diversion conditions near the sluice gate site, and a sufficiently wide construction site and favorable transportation conditions should be required. The selection of the sluice gate site should also consider the ease of management and operation of the sluice and flood prevention and emergency rescue after the sluice is completed, and at the same time, it should be combined with the layout of road bridges (or agricultural bridges) as much as possible. When the sluice is an integral part of a water conservancy project, the overall layout of the project should be compared, and the optimal position of the sluice should be obtained to meet the technically advanced and economically reasonable requirements.
2. Supplementary requirements
For the various sluices of the irrigation canal system, in addition to meeting the above common requirements, different supplementary requirements should be put forward for their work characteristics.
1) Intake sluice gate
For water intake sluice gates without a dam, the evolution of the river bed should be investigated and studied, and the sluice gate site should be selected as far as possible on the river section with a stable river bed and a stable river bank. For example, the intake gate of a canal on the bank of the Yellow River is located on a levee, and the foundation has been compacted over the years, and the soil condition is very good; the river is curved, and the mainstream is often leaning on the bank; the levee has better block stone protection; there are Other important projects can play a role in controlling the changes of the river course, so the river bed in this section is quite stable, and the construction of an intake gate can ensure the perennial water diversion. In order to make the inlet water flow smoother and minimize the bottom sand entering the channel, the inlet sluice should be arranged on the concave bank of the river bend as much as possible, and the gate site should preferably be located slightly downstream of the vertex of the concave bank of the bend. Under normal circumstances, the bending section of the month selection should not be too sharp, and the bending radius should not be less than three times the water surface. In addition, a suitable water diversion angle (the angle between the intake direction of the water diversion port and the river flow direction δ) should also be arranged. According to experimental research, when δ>30, the amount of destructive material entering the channel does not change much, and it is generally believed that the maximum is not more than 5%~15%, but it has a certain impact on the flow of the channel. Therefore, in order to increase the amount of water diversion and reduce the amount of sediment into the canal, the water intake angle of the side diversion should be as small as possible, and it should be selected between 30° and 60°.
As for the headgate of a dam to take water, of course, it should also be selected at a stable place on the river bank to ensure safety. At the same time, the height of the riverbank is required to be moderate to reduce the amount of excavation of stones on the channel. Intake gates are mostly located upstream or downstream of the end of the dam on the diversion side. When the river is relatively wide, the inlet gate can be arranged upstream of the dam (or barrage). When the river channel is narrow and the river bank is steep, the bank is not suitable for arranging the inlet gate, and the inlet gate and sand flushing gate can be arranged in the barrage (gate). In the open area in downstream, tunnels or diversion canals are used to divert the water to the headgate before the water is arranged on the upstream side, such as a clear water channel, the diversion angle of the sluice can be 90°. In most rivers, the diversion angle of the inlet sluice is mostly acute to reduce the loss of water head and the sediment content in the canal. According to Indian experience, the angle β between the front edge of the inlet sluice and the axis of the barrage (sluice) is taken as 105°~110°, that is, when the diversion angle δ is 75°~80° (Figure 1-5), the amount of sand entering the channel least. The intake gate is arranged on the downstream river bank. Generally, the water diversion channel is used as a sand sink in front of the gate, and a side sand sluice gate is set at the end of the sluice.
The main problem in terms of water flow is to keep the various buildings in the hub project from interfering with each other. For example, when there are ship locks or hydropower stations in the hub, they should be arranged on both banks of the river as far as possible from the canal head intake locks.
2) Drain sluice gate
In order to ensure the drainage effect, the sluice gate site should be selected on the drainage channel from the lowest point of the flood control area to the shortest drainage area. Drain gates are mostly built at the exit of the drain. Short drainage channels can reduce earthwork and channel head loss. In addition, the ground elevation at the sluice gate site is low.
When the drain sluice gate is located on the bank of the river, the outlet of the drain should also be located on the concave bank (or straight bank) of the river to avoid siltation at the outlet. The axis of the drainage channel should face the downstream direction of the river and intersect with the river flow at an acute angle. The angle of intersection should generally be less than 60°. The upstream and downstream channels of the gate should be straight, especially the downstream drainage channel. Harmful scour from the water flow under the sluice. During the drainage period, in areas where the river water level drops quickly, in order to avoid serious erosion behind the gate and ensure the safety of the gate, in addition to the necessary energy dissipation and anti-scouring facilities, sufficient length should be reserved for the downstream drainage channel of the sluice gate. In bad cases, there is enough water depth in the canal to prevent the water jump from pushing beyond the protective tank. At the outlet of the drainage channel, the bank protection and bottom protection of the river should be done to avoid the backflow erosion caused by the falling water level of the outlet.
The choice of the location of the drainage sluice gate is often related to the drainage method and economic benefits used in the entire drainage area. Sometimes it is better to build a large drainage gate in a location that can centrally control the entire drainage area than to build several small sluice gates in many locations. better. In this case, the main drainage channel is deep and wide, which can also be used for navigation. There are more opportunities for sluice gates to open, and the discharge is large, which is easy to wash away the sediment that may be deposited outside the gate. However, if the drainage area is large and scattered, and the route taken by the water from a distant place to the drainage sluice gate is too long, the time required for drainage will be prolonged, and the amount of excavation will also increase. At this time, consideration should be given to distributing the drainage sluice gates.
3) Discharge (Retreat) sluice gate
The selection of the position of the sluice has been introduced in the role of the sluice. When selecting the gate site specifically, it should be considered that there are larger drainage areas (such as lower-located rivers, lakes, drainage ditches or depressions, etc.) under the sluice gates and locations with short drainage canal lines, so that the water can be discharged quickly and smoothly, and the cost should be Low. The section between discharge structures (except for discharge gates, overflow weirs, siphons, etc.) should not be too long in order to discharge the floodwater into the canal in time. The sluice gate is permanent on one side of the channel, generally with a watershed angle of 60°~90°. A control gate can be arranged downstream of the sluice gate, or no control sluice gate can be arranged, depending on the specific conditions such as terrain and water flow. The retreat sluice gates, which are the remaining water volume of the retreat channel, are arranged at the end of the canal.
4) Sluice gates and control sluices
During the planning and design of the canal system, the location of the sluice gates and control gates should be determined. As the sluice gates for adjusting the channel flow, they should be arranged at the water distribution point from the upper-level channel to the next-level channel. However, the entrance of the sluice gate should not protrude from the upper-level channel in front of the sluice gate (Figure 1-6) but should be built backward and set on the canal bank.
The water diversion angle of the diversion gate is generally 60°~90°. The watershed angle of the bucket and the farm gate is mostly 90°.
When determining the location of the sluice gate and the control sluice gate, in addition to satisfying irrigation or other requirements, consideration should be given to building them together as much as possible. If the two sub-sluices can be brought together to use one control gate together, or several sub-sluices can be arranged together and used for each other, the amount of engineering can be further reduced and costs can be saved.
When the sluice gate or the sluice gate is also used as a sand discharge gate, it should also share a control gate with the diversion gate as much as possible.