應用分離元素法初探顆粒材料接觸與破壞模式之關係

Preliminary study of the relationship between contact and cracking behavior in granular material-numerical simulation and analysis

黃朝鍾(Chao-Zhong Huang)

指導教授 ： 張國楨

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00436

摘要

在野外探勘所觀察到的顆粒材料，例如：卵礫石，因岩體受力後造成礫石顆粒與顆粒間接觸點的接觸應力集中，接觸的礫石以接觸點為中心，造成多組破裂面相交、共軸，而呈現放射狀（星狀）破裂；破裂面上相交的中心軸，藉由一般地質上的統計方法來量取破裂軸的排列方向（接觸方向）；長久以來，此接觸方向一般視為區域之最大接觸力方向，或所謂最大古應力方向，為了瞭解顆粒材料在受壓情況下，當最大接觸力集中在一點的時候，其破裂方向是否會平行最大接觸力方向，亦或會產生些許角度的偏差，此推論仍存在著爭議性。本研究針對顆粒間微觀接觸行為進行分析，藉由分析三軸試驗、貫切模擬、改變材料參數等，期望有助於瞭解顆粒材料之變形行為。
本研究採用離散元素法PFC 3D模擬顆粒材料接觸受力的方向，藉由數值方法模擬顆粒材料受到擠壓後，顆粒間接觸方向及接觸力大小轉換的過程。設定不同微觀參數及不同的貫切形式，觀察顆粒接觸行為及接觸力的變化，包括推估最大接觸力的方向及顆粒接觸方向隨應變過程的角度變化情形。
當試體進行模擬三軸試驗及貫切試驗時，顆粒間的接觸行為受不同應變量、不同參數等的影響。結果指出接觸力的大小與接觸方向及試體破裂的方向有直接關係。

關鍵字

接觸方向 ； 分離元素法

並列摘要

Observed in the wild exploration of the particulate material, such as: gravel, because the force of rock particles and particles of gravel resulting from indirect contacts of the contact stress concentration point of contact with the gravel to reach the center, causing multiple rupture surfaces intersect, coaxial, while the present radial (star) break; rupture plane intersecting the central axis, by a general geological statistical methods to obtain the amount of broken shaft arrangement direction (the direction of exposure); For a long time, this contact with the general direction of the maximum contact force as a regional direction, or so-called maximum palaeo-stress direction, in order to understand particulate material under pressure, when the maximum contact force concentrated in one point, when the direction of its rupture would parallel the greatest contact force direction, or will they will have a little angle of deviation, this reasoning there are still controversial. In this study, micro-particle contact to be analyzed by analysis of triaxial tests, consistently cutting simulation, changing the material parameters and so on, which will help to understand the deformation behavior of granular materials.
In this study, discrete element method PFC 3D simulation of granular materials, access to the direction of the force, numerical simulation of granular materials by squeezing, the particle direction and the contact force between the contact size conversion process. Set different parameters and different micro-and coherent form, observe the behavior of particle contact and contact force changes, including estimating the direction of maximum contact force and the particle contact angle of the direction of the process of change with the strain the situation.
When the specimen to simulate triaxial tests and the proper test, the contact between the behavior of particles should be subject to different variables and different parameters studied. Results indicate that the contact force and contact direction and the size of the specimen is directly related to the direction of rupture.

並列關鍵字

Gravel deformation ； Maximum principal stress ； Distinct element method

參考文獻

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