圖書典藏及影音數位平台

蘭陽溪原名為宜蘭濁水溪，主流全長約40公里，以含砂豐富，水質混濁而得名，為宜蘭縣最大河川，屬中央管河川。現有防洪設施，迄至民國102年止，蘭陽溪主流部份計完成堤防50,724公尺，護岸790公尺。現況防洪構造物歷經多年風吹日曬、颱風豪雨及多次強弱地震影響，已有略呈堤頂下陷、淘空滲砂與材料劣化等現象發生，對於現況防洪構造物的安全性影響極大，故有必要針對堤防構造物進行調查及檢測。歷經民國101年蘇拉颱風等沖刷影響之後，造成堤防受損極需評估其安全性。然而全河段拆除重建工程經費龐大，且蘭陽溪堤防多屬老舊堤防，為能尋求有效維修與補強方案，擬藉由安全性評估計畫來全面檢視蘭陽溪堤防之安全，以利後續維護管理。本計畫主要目的為暸解蘭陽溪堤防內容結構現況，採用非破壞檢測方式，檢查堤防構造物之使用狀況與內部損壞狀態，包含結構體內部裂縫及含水狀況等情形，以便未來做為堤防管理、維護之參考依據，以及尋求有效維修與補強方案，擬委外辦理安全性評估分析及研擬改善方案。

The Lanyang Creek System is the largest one inside Ilan County administered by the central government; its main tributaries include Luodong Creek and Ilan River. The scope of this project consists of dikes on the right bank of the main branches such as Wujie, Dachou, Inxizhou, Inxizhou Bulkhead, Hungchailin, Sanshing NO.2, Sanshing Old Bulkhead, Sanshing NO.1and Pobuwu in the total length of 26,918 meters. The existing structures of flood wall of the creek system were found partially collapsed, hollowed out, and material deterioration due to long years of weathering effect and struck by typhoon and heavy rains. Especially, after the erosion impact brought by Typhoon Saola in 2012, Typhoon Tembin in 2013, Typhoon Matmo in 2014, serious damages were done and the safety needs to be evaluated. In order to look for effective maintenance and reinforcement initiatives, we conduct this safety evaluation and analysis project and propose the initiative for improvement for the reference of future management and maintenance. The project consists of two parts: dike inspection and data collection, analysis, and compiling. The former includes: on-site investigation of dike structures to cover the scope of right bank of Lanyang Creek. In three on-site visits, 38 damaged parts were identified. After visual inspection on damages, 34 sites need to be improved by this project and four need to be observed. Damage types are mainly caused by cracks, about 28 sites, followed by six pothole damages. Additionally, the non-destructive testing is conducted on erosion with the ground-penetrating radar to complete the measurement length of 36,211.5 meters. It was found that 508.5m of dike was slightly cleaned out, 4.5m of dike was intermediately cleaned out, and no dike was seriously cleaned out. Furthermore, through the cross-examination of radar testing, impact-echo method, rebound hammer method, and core testing, similar empirical proofs were identified. Thus, this project utilized ground-penetrating radar to inspect dike structures to fully understand the current state of them. This project adopts six indicators for evaluation: visual inspection result, non-destructive testing result, historical information of dikes, dikes preserved, evaluation of dike structures, environmental factors, and hydraulic analysis evaluation. Every 100-meter dike was marked as one section for evaluation; 220 sections were found normal while 46 were required to be improved by the project, and four need to be observed where are located at four sections of Wujie Dike 7K+940~8K+040, Dachou Dike 2K+900~3K+000, Pobuwu Dike 1K+300~400 and 1K+500~600. We suggest that intense monitoring is required and the budget shall be allocated for repairing. The 46 sections that need to be improved by the project shall be listed for regular inspection and monitoring. Additionally, for the total of 38 damage sites, please refer to Chapter 6-4 for repairing evaluation and analysis. The amount for maintenance and repairing totals 2.67 million.