砂岩摩擦降伏後之潛變特性;Creep properties of sandstone after frictional yielding

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Title:	砂岩摩擦降伏後之潛變特性;Creep properties of sandstone after frictional yielding
Authors:	彭聖祐;Peng,Sheng-you
Contributors:	土木工程學系
Keywords:	摩擦試驗;潛變破壞;破壞時間;加速度;音波
Date:	2015-07-09
Issue Date:	2015-09-23 10:03:49 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究以微音器與加速度計量測砂岩摩擦試驗時之音波與振波訊號，探討砂岩試體降伏後再施加不同摩擦應力使其產生潛變破壞所耗之時間。試驗中所測得之音波與加速度訊號可協助判定潛變變形或破壞發生之時間點。由研究結果顯示，砂岩潛變破壞，隨降伏後應力之增高，而破壞時間逐漸縮短；隨降伏後的應力之減小，破壞時間逐漸增長。此結果說明了降伏後的應力增加會加快岩石層面的潛變破壞。另外，降伏後的應力為降伏至破壞間應力差的50%以下，砂岩試體並無破壞情形，顯示破壞時間長，且無立即危險，當降伏後的應力達50%以上，實驗結果顯示試體有立即破壞之危險。由量測結果可知降伏後的應力達50%以上之情況，破壞時間介於0~36秒，降伏後的應力為50%以下之情況，破壞時間超過兩天，如輔以加速度與音波之警訊，可作為預警危急程度之判定，將可降低災害的損失。;This research performed a series of frictional tests of sandstone specimens. In these tests, various frictional stresses were applied to study the required time for creep failure, and measuring sound wave and vibration wave signals to distinguish creep deformation and failure. According to the experimental results, for a post-yielding stress closer to the failure frictional strength, the creep failure time will be shorter. And for a post-yielding stress closer to the yielding stress, the creep will last for a very long period or it may not fail. These experimental results indicate that applying a stress after yielding will accelerate sliding deformation of sandstone and causes failure. Besides, when applying a post-yielding stress which is less than 50% of the range between yielding and failure, sandstone specimen will be under a safe state. However, if the post-yielding stress is larger than 50%, the failure of sandstone specimen will happen rapidly. When friction stress is more than 50% of post-yielding stress, the failure time is ranged between 0 and 36 seconds. However, failure will last more than two days for the post-yielding stress less than 50%. With the assistance of sound and acceleration signals, the combination of these information measured from rock slope may be used as a tool of early warning.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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