透地雷達應用於地層裂隙之研究

Research on Application of Ground Penetrating Radar to Formation Fissure

李世賢(Shih -Sian Li)

指導教授 ： 游峻一

健行科技大學/工程學院/土木工程系空間資訊與防災科技碩士班/碩士(2020年)

摘要

澎湖群島由近百個大小島嶼、岩礁組成，島嶼的岩質除花嶼外，均由數層玄武岩的熔岩流和部份夾層的沈積岩所組成，據地質學者指出，澎湖的玄武岩經數次不連續的火山活動後，熔岩從淺海或地下裂隙湧出地面因快速冷卻，收縮龜裂成五、六角形柱狀體，此現象稱為「節理」。節理構造的多樣性變化，可說是澎湖玄武岩最特殊的自然景觀。
本研究於白沙國中操場與外垵之崩塌地進行調查，藉由透地雷達的施測，瞭解白沙國中部分操場地面龜裂原因及利用外垵現有崩裂之地，推測未來可能崩塌的地方。由透地雷達的施測顯示，白紗國中操場地層均十分均質，並未有不連續情況發生，較堅硬之地層推測應在地下0.5至0.6公尺之間，風化層應不超過1公尺，並推測表層地層龜裂可能原因為東北季風帶走地表水分而引發之表層地層乾裂，非為地底下有塌陷或孔洞而造成的結果。外垵崩塌地在測線1長度10至10.8公尺、測線2長度5.8至6.8公尺及測線3長度5.8至6.8公尺處，深度0.6公尺的強反射面無顯現，依據此三條測線之連線推測應為下一次崩壞可能地點。

關鍵字

澎湖 ； 玄武岩 ； 透地雷達法

並列摘要

Penghu is composed of nearly a hundred islands and ledges. Except for Hua isle, the rocks of the islands are composed of several layers of basalt lava flow and some intercalations of sedimentary rocks. According to geologists, lava gushed out of the ground from shallow seas or underground fissures due to rapid cooling, shrinking and cracking into pentagonal or hexagonal columns after several discrete volcanic activities, this phenomenon is called "joint". The diversity of joint structure is arguably the most special natural landscape of Penghu basalt.
This study used ground penetrating radar to investigate the causes of the ground cracks at Paisha Junior High School playground and peculate where it might collapse in the future at existing cracked area of the collapse in Waian. The result shows that the strata are very homogeneous and there are no discontinuities at Paisha Junior High School playground. The harder strata are supposed to be between 0.5-0.6 meters in depth and the thickness of the weathering layer should not exceed 1 meter; It is also speculated that the cracks in the surface may be due to the surface layer dry and crack caused by the northeast monsoon took away surface water, which is not caused by subsidence or holes under the ground. The strong reflection surface does not appear in depth of 0.6 meters at 10-10.8 meters of line 1, 5.8-6.8 meters of line 2 and 5.8-6.8 meters of line 3 at the collapse in Waian. These three sites in a line should be the possible location of the next collapse.

並列關鍵字

Penghu ； basalt lava ； ground penetrating radar

參考文獻

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