Hanchuan sluice is located at pile number 65+050 on the left bank of the main dike of Hanjiang River. The sluice is a flood control sluice, which was started at 195 1 and completed at 1953. The sluice is an open reinforced concrete box structure, with the floor elevation of 18.30m, the crest elevation of 3 1.30m, 3 holes, the clear width of each hole is 4.0m, the clear height is 6.0m, the width of the sluice chamber is 130.50m；, the length of the sluice chamber is 33.8m, and the design flow is 474m3/. Drainage conditions: the water level of the inner lake is 23.00m~27.00m, and the water level of the outer river is18.68 m ~ 30.24 m. After the completion of the sluice, it has played an important role in agricultural production in Diaochahu Lake area.
In order to further understand the causes of cracks, the owner entrusted the Institute of Materials and Structures of the Yangtze Academy of Sciences to conduct sampling tests on the concrete and steel bars of the pier and bottom plate. The conclusion of the inspection report is: (1) The crack surface of the pier is wide and gradually becomes smaller towards the inner side of the pier. (2) The maximum carbonation depth of concrete is 6.0mm) The compressive strength of uncarbonated concrete is 37.6MPa ~ 53.7MPa) The alkali-aggregate reaction characteristics of concrete are not obvious. (5) Except for concrete cracks, there is no steel bar corrosion.
2, engineering reinforcement design scheme
Through technical and economic comparison, the scheme of braking first and then braking is adopted. After demonstration and analysis, the scale of the new sluice can close the holes on both sides of the old sluice, leaving only one hole in the middle.
3. Engineering Geology
The geological exploration of the new culvert shows that the project area is the first terrace of Hanjiang River. From top to bottom: 18.2m~ 17.40m, muddy silty clay, grayish black, soft plastic. This layer is below the hole body of the new sluice, which was completely excavated when the old sluice was built and the entrance blanket was laid. 17.40m~ 16.20m, yellow-brown clay, containing ferromanganese points, plastic state, standard value of bearing capacity fk= 150kPa, compression modulus Es=5.63MPa, standard value of friction around pile qs=25kPa. 16.20m~ 14.60m, muddy clay, gray-black, plastic mica sheet, standard penetration of 5 blows, standard bearing capacity fk= 1 10kPa, compression modulus Es= 1.8MPa, friction around the pile. 14.60m~5.40m, silty sand layer, gray-black, saturated, slightly dense ~ moderately dense, uniform in texture, with a thin layer of silty clay in the upper part and fine gravel in the lower part. The SPT blow count is 8~25, and the standard bearing capacity is fk= 180kPa above 0.00 m, and fk below 0.00 m. The standard bearing capacity of bored pile tip is qp=750MPa.
4. Reinforcement design of sluice project
4. 1 design standard design water level combination: design flood control conditions: the water level of the inner lake is 23.50m, and the water level of the outer river is 31.69m; ; Check the flood control conditions: the water level of the inner lake is 23.50m, and the water level of the outer river is 32.19 m; Drainage conditions: the water level of the inner lake is 25. 14m, and the water level of the outer river is18.97m.
4.2 Design guiding ideology (1) Each part of the newly-built culvert gate is independently stressed to retain water, which is close to but not connected with the old gate. (2) The environmental construction of the sluice area should be fully considered in the project layout. (3) Make full use of the energy dissipation and scour prevention functions of the existing stilling basin and flood plain. (4) Make full use of the anti-seepage function of the original building.
4.3 Engineering Layout and Design (1) Hole Layout. The new culvert gate is of culvert type, with the central axis of the tunnel body consistent with that of the old gate, and the orifice size is 5.5m×4.8m Due to the limitation of the existing blanket on the inner lake side, the lowest floor elevation can only be set at 19.50m, and the slope of 1: 3.5 is adopted to connect with the floor of the old gate, and the highest elevation is 25.00m. According to the requirements of urban construction and seepage control, the length of the tunnel body is 36.00 meters, and the flood gate is located on the outer river side. The upper part of the tunnel is filled to 3 1.30m, which is consistent with the elevation of the old sluice top, so as to cooperate with the urban construction. Reinforced concrete waterproof wall is used above 3 1.30m, and the top elevation of waterproof wall is 33.00m, which is 0.8 1m higher than the check flood level. The new gate opening and closing chamber and the old gate opening and closing chamber together constitute the new gate life management facilities. The top of the embankment consists of a road surface with a width of 14.00m and sidewalks with a width of 1.50m on both sides. Temporary asphalt pavement is paved on highway pavement, and precast concrete blocks are paved on sidewalks. Embankment slope is consistent with environmental greening construction. (2) The hole plugging engineering arrangement on both sides of the old sluice. Because the actual bearing capacity of the pile foundation of the old sluice is not specified in detail, the basic principle of the arrangement of water retaining structures on both sides of the old sluice is still the same as that of the cave, and the buttress retaining wall is adopted on the lake side of the old sluice. (3) Connecting the buildings on the inner lake side. The connecting building at the entrance of the inner lake adopts an arc buttress retaining wall with r = 10.00 m, and the top elevation of the retaining wall is the same as the upper elevation of the culvert top, which is 26.00 m. (4) Foundation treatment. The bearing capacity of natural foundation in pile foundation design is low, only 1 10kPa. According to the design experience of other similar projects and the requirements of relevant design codes, in order to save the engineering quantity, the bearing capacity of natural foundation should be reasonably utilized. Therefore, in the design, we adopted the design method of pile-soil interaction. That is, under the premise of not exceeding the allowable bearing capacity, the natural foundation should bear 40% of the upper load and the pile foundation should bear 60%. Pile foundation layout is as follows: ① Hole body: in the downstream direction, a row of piles are arranged along the wall surfaces on both sides of the hole body, and the pile spacing gradually changes from 2.50m to 3.00m in the downstream direction, and the vertical spacing is 6.00m m. The diameter of the piles is 800 mm, and the length of the piles gradually changes from 24.00 m to 20.00 m with the stress. ② Retaining wall: Pile foundation layout mainly solves the problems of insufficient bearing capacity of natural foundation and uneven settlement control. The diameter of the pile foundation is still 800mm, because the two retaining walls at the old sluice are blocked, the foundation stress at the front teeth is large, and it is limited by the geological layer, so the length of the pile foundation cannot exceed 24.00m (if it exceeds 24.00m, it will enter the sandy pebble layer, and the construction is very difficult. ) Therefore, the pile spacing is relatively close, with a minimum of 2.00m (equivalent to 2.5 times the pile diameter, reaching the minimum allowed by the specification). (5) Repair and reinforcement of existing buildings. There are two sluices between the old and new sluices. The first one uses traditional copper sheets to stop water, and the second one fills water-stopping polyurethane outside the copper sheets. Crack reinforcement of stilling basin; Repair of mortar block stone in overflow section of outer river and sea; Waterproof walls are built on the tops of barbed walls on both sides of the old sluice. The top elevation of waterproof wall is 33.00 meters, and it adopts reinforced concrete structure. A new hoist room, flat steel gate and corresponding electromechanical equipment were built. After the completion of sluice reinforcement in 2000, the danger was basically relieved and it has been running safely so far.
I believe that after the above introduction, everyone has a certain understanding of how to strengthen flood control sluice. Welcome to Zhong Da for more information.
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