單速與不同頻率變速旋剪試驗條件下高嶺土之速度與位移相依摩擦律

Velocity-displacement dependent friction law of pure kaolinite based on constant and oscillatory rotary shear tests

賴俊融(Chun-jung Lai)

指導教授 ： 董家鈞

國立中央大學/地球科學學院/應用地質研究所/碩士(2015年)

摘要

單速旋剪摩擦試驗在過去幾十年中成功地被用來探討斷層力學與大型山崩滑移。近期研究顯示，集集地震誘發之草嶺山崩在快速滑動前，藉由Newmark分析可以觀察到山崩塊體在觸發階段時有加速與減速的運動，此一結果顯示在加減速條件下，較能符合地震及山崩之滑動過程，因此以加減速條件研究滑動面摩擦特性有其必要性。本研究利用根據單速旋剪摩擦試驗所建立之速度與位移相依摩擦律，模擬在加速減速滑移過程中斷層泥摩擦係數的改變，並與前人研究比較，結果發現在變速度實驗過程時，在滑移速度降至零時，剪切材料之強度會回復至最大值，與實際震盪速度試驗結果不符。因此本研究進一步利用純高嶺土進行單速與加、減速旋剪試驗，並根據試驗結果，建立高嶺土之速度-位移相依摩擦律，本研究建議之摩擦律納入了加、減速行為、最大速度，以符合加減速試驗所觀察到的摩擦係數回復值隨頻率增加而減小的現象，並可進一步應用於地震斷層動力學或地震誘發山崩之觸發機制。

關鍵字

速度位移相依摩擦律 ； 旋剪試驗 ； 變速度 ； 頻率

並列摘要

Rotary-shear friction experiments have been successfully used to study the earthquake dynamics and catastrophic landslides in the past two decades. In addition, the oscillating movement was observed in Tsaoling landslide by Newmark Analysis. Recent studies indicated that the friction behaviors of fault gouge materials under oscillatory shear are different from those under constant shear. Previous experimental results revealed that the accelerating and decelerating motion caused weakening and strengthening, while undergoing overall slip-weakening. In this study, we try to approximate the temporal variation of friction coefficient during accelerating/decelerating slip based on a velocity-displacement dependent friction law derived from constant rotary shear tests. The approximated results show a full strength recovery behavior when the slip velocity reduced to zero, which cannot depict the experimental results. Therefore, we conducted a series of the oscillatory velocity experiments with pure kaolinite to establish a new velocity-displacement dependent friction law. The mechanisms behind the differences of friction behaviors between the oscillatory and constant rotary shear tests will be explored.

並列關鍵字

Velocity-displacement dependent friction law ； Rotary-shear test ； Friction coefficient ； Oscillatory velocity ； frequency

參考文獻

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