圖書典藏及影音數位平台

曾文水庫為台灣庫容最大之水庫，亦為嘉南地區最主要之水源，兼具灌溉、給水、發電及防洪功能。民國98年莫拉克颱風降下超大豪雨之侵襲下，曾文水庫上游集水區邊坡崩坍嚴重，進而加速水庫淤積惡化之情形，並嚴重影響水庫容量與防洪運轉操作。為使曾文水庫後續相關治理計畫能維持水庫營運功能、保育上游集水區水域環境及穩定水庫供水能力，本局依據「曾文水庫水力排砂等可行性規劃調查設計」計畫之評估成果，自民國101年起規劃辦理「曾文水庫永久河道放水道(PRO)改建防淤設施工程」，期藉由颱洪期間以水力排砂方式，將底層高濃度泥砂排放至下游，以降低壩前淤積高程，延長水庫使用壽命。 PRO改建防淤設施工程為提升排砂能力，原何本閥已改建為全斷面射流閘門，最大流速近30 m/s 之含砂水流自射流閘門射流(設計流量為177 cms)衝擊至消能工消能後，將迴流由消能工頂版之孔道 (0.5 m×90 m) 經1號導水隧道放流至曾文溪，當高流速含砂水流持續沖擊隧道內混凝土構造時，可預期將產生磨耗甚至損毀情形，影響結構體之安全性。因此，為瞭解及掌握PRO射流閘門執行排砂後之隧道各部位磨耗及損傷狀況，有必要在排砂操作後隨即進行隧道內混凝土構造之磨耗檢測，並進一步分析所得資料，其結果除可作為爾後PRO排砂運轉操作之重要參考外，並可據以研定適切之維護或修復計畫，確保導水隧道之營運安全，爰辦理本委託案。 曾文水庫防淤隧道工程竣工後，防淤隧道與1號導水隧道可能進行水力排砂聯合運轉操作，為確保防淤隧道與1號導水隧道聯合操作之安全，爰將防淤隧道環氧樹脂砂漿抗磨層納入檢測。

The main scope of work of this project is the No. 1 water-conducting tunnel from the energy-dissipating ring to the second downstream stern, including the structures above the water surface in the tunnel (including the invert arch, the side wall and the first stern structure), and The anti-sludge tunnel epoxy resin mortar is from 0k+000 to 0k+800 downstream of the gate shaft section. The No. 1 water-conducting tunnel is discharged in August from August to September, respectively. The total number of hours is 354 hours; Between 5 – 100 cms, the time for releasing 100 cms is 39 hours; the total water discharge is 69.89 × 106 M3. The total discharge time of the anti-silting tunnel is 299 hours, the water discharge is between 50 – 650 cms, and the total water discharge is 333.18×106 M3. During the execution of this project, a total of 1 three-dimensional laser scanning in the No. 1 water-conducting tunnel, 2 times of guided wave and precision resistance concrete abrasion detection, 2 times of first-span steel plate ultrasonic abrasion detection, 3 times of pumping operation, and wear resistance were performed. On-site operation of concrete layer wear/detection 4 times. 1. Establish 3D image and analysis in No. 1 water diversion tunnel This year, the difference between the single-point comparison results of 106.06.09 (the initial value after the restoration project) and 108.10.18 was performed from the 3D scanning results of the No. 1 diversion tunnel. No. A8, A9), the difference is 34.2cm-33.6cm. This result is close to the actual measurement on site. The main wear depth is caused by the water discharge operation during July-August. Another big difference is between the first tail sill and the second tail sill (points A3, A4), and the difference is about 16.7cm-19.2cm. In addition, the results of the comparison between 107.10.12 (after the 107-year damage) and 108.10.18 showed that, except for the repair at points B7 and B8, which are not obvious due to wear, and highlight 19.1-21.5cm, the rest of the wear area is different from the year 107. Not big. 2. Abrasion detection of concrete structure of No. 1 diversion tunnel The main damage of the No. 1 diversion tunnel occurred within 2m upstream of the first tail sill, and the wear in the remaining areas was not obvious. The damage of the upstream end of the first tail sill is that the wear of the concrete on the left and right sides is small, the wear depth of the middle part is large, the steel bar and the bottom steel plate are exposed, and the maximum wear depth of each section is between 7-40 cm; overall wear The situation is similar to the year 107, but the scope is small. In addition, the wear depth of the six triangular cones located in the bottom of the first tail sill and the second tail sill is 2.5-3.9 mm more than that of the previous year. 3. Visual inspection of anti-wear layer of anti-fouling tunnel epoxy resin mortar There is no cracking or swelling of the epoxy mortar layer in the anti-fouling tunnel, but there are many scratches, abrasion and peeling of the epoxy mortar layer of the lining, including the interface peeling gradually expanding to the flakes being lifted and peeling and the wear depth gradually deepening. situation. On the left and right side walls, scratches ranging from 0.5m to 12m in length appear, and some of the scratches are as deep as the concrete surface. 4. Analysis of abrasion test data The main cause of concrete damage in water diversion tunnels is estimated that when the water discharge volume reaches 100 cms, the strong jet water is blocked by the first tail sill, and the strong hydraulic pressure caused by the eddy current at its toes makes the wear-resistant concrete and the first Fracture occurred at the junction of the tail sills, which eventually led to large pieces of concrete spalling and breaking the steel bars. On the other hand, the wear and tear of the oxyresin mortar layer of the anti-fouling tunnel is usually not caused by a single action. The mechanism of wear and tear that occurred this year was mostly a combination of (impact wear of muddy water flow) and (frictional wear of sliding or rolling of solid objects). Under this joint action, when the epoxy mortar and the concrete interface of the bottom layer are poorly bonded, the epoxy mortar will peel off in a large area, and the concrete is prone to obvious erosion marks or small depressions, and this situation is mostly repaired ; If the interface is good, the surface will be scratched and the thickness will gradually decrease. The former is the main wear and tear of this year, so the interface treatment of epoxy resin mortar repair needs to strengthen its adhesion.