岩石邊坡潛變變形之模擬分析

Simulation on the Creep Deformation of Rock Slopes

周令麒(Lin-Chi Chou)

指導教授 ： 陳天健

國立屏東科技大學/工學院/水土保持系所/碩士(2014年)

https://doi.org/10.6346/NPUST.2014.00239

摘要

本研究以高屏溪流域的板岩邊坡為例，運用分離元素法模擬板岩受到長時間重力作用下產生的潛變行為。本文採用Chigira (1992)與Richard (2000)學者研究之潛變型態，利用分離元素法進行潛變因子研究，配合現地調查之野外潛變產狀，以期了解其成因及機制。弱面平緩岩體，其潛變型態常為折彎褶皺型，在數值模擬中亦可獲得類似之型態，但在不同的材料和地形條件下，所形成的潛變型態有些微的不同。其次在研究成果中顯示在同一傾角之弱面狀況，當弱面為角度小於45度之平緩傾角時，其受到重力作用下滑，岩體受到擠壓，所呈現的潛變型態多為折彎褶皺型；而角度大於45以上之高傾角岩體，弱面受到重力作用，所呈現的潛變型態多為表層岩體之傾倒現象。
在弱岩石強節理的條件下，滑動過程中會呈現塊體彎曲的情形；強岩與弱節理的條件下，滑動過程中會呈現塊體分離的情形；弱岩與弱節理的條件下，滑動過程中塊體會變形，順著弱面方向下滑的情形；在逆向坡高傾角強岩及弱節理的條件下，塊體會呈現傾倒，且因節理發達會呈現塊體分離的情形。
河川下切作用方面，河岸下切角30度時，其由下邊坡表層開始產生褶皺，而後逐漸向坡頂發展，形成多個波浪狀的潛變；河岸下切角45度時，其弱面傾角因小於坡角，將出現塊體滑動，但在表層與底層的接觸面，仍有擠壓造成的隆起。

關鍵字

板岩 ； 潛變 ； 數值模擬

並列摘要

This study on the slate creep behavior in Gaoping River was performed by the discrete element method. In this paper, Based on the rockmass creep patterns by Chigira (1992) and Richard (2000) and the field observation, the essential boundary and material condition and the mechanism of the creep are studied by UDEC simulation. The bending fold of a creep rockmass occurs frequently in the lower angle jointed slope while the numerical simulation obtain the similar result. Furthermore, the creep pattern converted as under the different materials and terrain conditions. The results shows when the joints inclination angle less than 45 degrees, caused by gravity, the rock mass yields the bending fold type of creep; On the other hand, for the one’s inclination angle is greater than 45 degrees, the rock mass yields the topple on the surface of slope.
In the weak rocks with strong joints condition, the rock mass will yields a bending fold; next, in the strong rock with weak joints condition, the rock mass yields a block sliding; oppositely, in the weak rock with weak joints condition, the rock mass will slide and bending along weak plane; last, the anti-dip slope with steep angle in the strong rock with weak joints, The rock mass experiences the topple and falling down to slope in block.
River erosion effect is also studied by cutting the foot of river bank in several slopes in numerical model. The results show the multiple small folds occurred from the toe to top of slope under the 30 degrees of river bank. Moreover, the discrete block sliding on surface of slope, and the squeezing at toe of slope are occurring under the 45 degrees of river bank.

並列關鍵字

slate ； creep ； UDEC

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