目前較常使用的土壤改良工法為水泥化學灌漿或高分子漿液之工法，但近年來環保意識抬頭，化學灌漿之人造合成材料多可能會危及到大自然環境，因此較為環保之改良工法逐漸被學者們研究與應用，例如微生物引致碳酸鈣沉澱(MICP)。此技術為一種利用微生物化學反應改良土壤工程性質的技術，本研究之目的為探討微生物引致碳酸鈣沉澱改良技術應用於邊坡在強降雨下之破壞行為。
研究中使用微生物改良技術先進行室內重模土壤的力學性質試驗，改良後土壤的滲透性較改良前降低約38%，在CPT貫入試驗中，改良試體的錐尖阻抗增加約90 kPa；此外利用排水三軸壓縮試驗，得到MICP改良土壤之凝聚力c'增加2.41 kPa，而內摩擦角φ'與未改良土壤相比，有微幅的增加。本研究亦利用改良後的土壤參數進行數值分析，得到其改良前後的模擬分析結果。
本研究亦進行縮尺模型試驗，縮尺率(Scaling law)為N = 5，長為65公分、高30公分、坡度40度的縮尺邊坡，並透過影像分析技術分析邊坡變位，求得破壞面上土壤剪應變發展。結果顯示在降雨強度80 mm/hr的條件下(100年重現期距)，改良後破壞範圍較改良前破壞範圍小，邊坡也呈現出較良好的自立性，改良後的邊坡在100年、200年重現期距、甚至極端氣候條件下都沒有造成大規模的土方滑落坍方現象，也有助於阻擋水的滲流，延長坡腳局部崩落破壞的時間。

At present, the more commonly used soil improvement methods are cement chemical grouting or polymer slurry methods. But in recent years, environmental awareness has increased, and chemical grouting of man-made synthetic materials may endanger the natural environment, so more environmentally friendly improvement techniques are gradually being studied and applied, such as microbial-induced calcite carbonate precipitation (MICP). This technology is to modify soil engineering properties using microbial chemical reactions. The purpose of this study is to investigate the application of microbial-induced calcite carbonate precipitation improvement technology to slope failure under heavy rainfall.
The mechanical properties of the soil were first tested indoors using microbial amendment techniques, and the permeability of the amended soil was reduced by about 38% compared to that before the amendment. In the CPT penetration test, the cone tip impedance of the modified specimen increased by about 90 kPa. The cohesion of the MICP-improved soil increased by 2.41 kPa and the friction angle φ' has a slight increase compared to the unimproved soil. In this study, numerical analysis was also conducted using the improved soil parameters to obtain the simulation results before and after the improvement.
In this study, a reduced model with a scaling law of N = 5, a reduced slope of 65 cm in length, 30 cm in height, and a slope of 40 degrees was also tested, and the soil shear strain development on the failure surface was analyzed by image analysis techniques. The results showed that under the condition of 80 mm/hr rainfall intensity (100-year return period distance), the failure extent after improvement was smaller than that before improvement, and the slope also showed better self-supporting, and the improved slope did not cause large-scale soil slide slumping under 100-year, 200-year return period distance, or even extreme weather conditions, which also helped to block water infiltration and extended the time of local failure at the foot of the slope.

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