利用地表微振動判釋地層特性與地震災損之研究－以台南、高雄為例

地震，是台灣常見的自然現象，但往往帶來不容小覷的災害，2016年2月6日發生的美濃地震，造成了台南地區許多災害，包括大樓倒塌以及多數地區發生土壤液化災害。一個基地要判定是否容易發生地質災害，在傳統作法上常使用標準貫入試驗（SPT）或是圓錐貫入試驗（CPT）的探測結果進行分析，但此二種試驗方法常受到時間、經費、施作空間等之影響，而且曠日廢時或不易執行。因此本研究使用微振儀經由單站頻譜比法分析，以微振動建立一種快速且簡便的判釋地層特性的方法。研究首先收集微振動得到之H/V頻譜圖，利用其地層放大係數（H/V）值建立其與同一地點的SPT-N值與地層深度的關係，再以台南、北高雄區域的鑽探資料為基礎，建立以微振儀的探測結果來判斷土層特性之方法，進而將微振動分析所得到之地層卓越週期，經由地理資訊系統以內插法應用於本研究區域，並與0206美濃地震發生災損之地點進行疊圖分析，探討地層卓越週期與毀損建築物的基本振動週期之關係。由研究結果發現，毀損建築物大多位於結構物基本振動週期與地盤的卓越週期相近之區域，探討此關聯性可提供建築物在設計規劃時，預先避免未來在地震時結構物與地盤產生共振破壞災害的參考。

關鍵字

微振動；標準貫入試驗；地震災害；卓越週期

並列摘要

Earthquake is a natural phenomenon which brings significant damage to the modern society. On February 6, 2016, Meinong Earthquake caused extensive damage, including the collapse of a high-rise building and soil liquefaction, in Taiwan. Conventionally, the SPT and CPT technologies are applied to assess the disaster potential of a site. However, time consuming, economic cost, and working space are three major impacts to constraint the progress of the in-situ tests. This study proposed a fast and simple method to interpret the physical/mechanical characteristics of the ground using single-station microtremor with Horizontal-to-Vertical Spectral Ratio (HVSR) analysis. This study firstly obtains the H/V spectrum to establish the correlation between H/V and SPT-N under different depth. In addition, a microtremor-based detection method is developed to judge the soil characteristics by comparing the borehole data in Tainan and north Kaohsiung. The predominant period at each measuring station is applied associating with interpolating method to draw a contour map in GIS. Then, the correlation of predominant period between the ground and the buildings are discussed using the structure damage data in Meinong Earthquake. The study figures out that most damaging structures are located at the ground whose predominant period are close to the structural one. Therefore, during the structure design, engineers must avoid the occurrence of resonant damage during an earthquake in the future.