背拉擋土牆地錨之防蝕處理與檢測

Corrosion Protection for Tie-back Anchor of Retaining Wall and its Inspection Method

工作地錨之長期行為可分別從地錨荷重的穩定性和地錨構件之防蝕效果兩方面來量測。針對地錨長期行為之確保問題，本研究提出下列具體的做法，包括永久性地錨中錨碇段之現地樹脂灌注法與量測錨腱和周遭環境間電阻之防蝕保護電阻量測檢測法。但這些方法對應用於坡地工程之背拉式擋土結構的實際適用情形，尚缺有系統的本土化實驗結果供工程界參考，故本研究藉由坡地工程試驗站之現場足尺寸試驗來印證上述各方法之適用性。結果顯示：經過約一年半的時間，以防蝕保護電阻量測檢測法結果得到錨腱和周遭環境間電阻由原本剛鎖定完的155.9 MΩ降低至趨近於0 MΩ，顯示防蝕效果明顯下降，初步判定原因應為樹脂灌漿體在這段時間開裂，並且因此導致地下水滲入地錨組件中。故以樹脂作為現場永久地錨灌漿材料可行性高，但現場拌和的樹脂耐久性需要更進一步的改良與研究。

The long-term behavior of working ground anchors can be measured from the long-term stability of lock-in anchor load and the effectiveness of anti-corrosion measures for anchor components. To do so, the following measures have been taken and tested in the field including insitu resin grouting method for the fixed anchor end and the measurement of electrical resistance between anchor components and surrounding ground. After a period of one and a half year, the test anchor showed minor decrease in lock-in load. But the electrical resistance dropped significantly from 155.9 MΩ to almost 0 MΩ. It indicated that the resin grout might have cracked over that time period and groundwater managed to seep into the corrosion protection measures and contacted the anchor components. So, the process of in-situ resin grouting may be feasible during anchor installation. But the durability of field mixed resin needs to be further improved to ensure its long-term performance on corrosion protection.