以PFC模擬分析處置孔間裂面受熱應力錯動行為

本研究主要以顆粒流PFC程式，來模擬雙處置孔間岩柱在完整或存有一既有節理條件下，先後因開挖應力調整之力學耦合(Mechanical couple)作用、及其後於不同時間先後放置核廢料處置罐狀況下，受熱應力作用的力學-熱力耦合(Thermo-Mechanical couple)作用之岩石裂隙發展微觀機制。本文首先：(1)利用單軸壓縮試驗與直接拉力試驗進行微觀參數分析，以了解微觀參數之相互影響，並以前人所歸納之離島花崗岩力學性質進行輸入參數的訓練與數值校正，得到一組合格之參數組合；(2)針對不同角度下之既有節理條件下，分階段進行單孔開挖，探討双處置孔間岩柱之力學耦合行為，與節理之錯動及張開行為；(3)完成開挖後，分別進行先後與同時加熱處置孔壁外圍，探討熱-力耦合作用所產生的岩石損傷與節理面錯動行為。本文主要獲致結論如下：(1)岩石單壓強度(UCS)之關鍵微觀影響因子有平行鍵結抗拉強度(pb_ten)、平行鍵結凝聚力(pb_coh)、勁度比(k_n/k_s)；(2)左孔開挖造成岩柱內與處置孔方向垂直的節理(H90H joint)產生的張開量最大，而在斜向節理(H45H joint)的切向錯動位移量最大；(3)完成雙孔開挖後，與處置孔方向平行向的節理H0H joint與直向的節理H90H joint之節理面中心張開量皆比兩端大；(4)左孔先受熱後，平行向節理H0H joint狀況下錯動最為明顯，在節理面張開量上，平行向節理H0H joint左側及中心位置隨受熱後逐漸增加，H45H joint中心位置增加量較為明顯，與處置孔方向垂直的H90H joint在受熱後則發生閉合現象；(5)於左孔受熱完成後，再進行右孔受熱，平行向節理H0H joint與H45H joint狀況下錯動較為明顯，在節理面張開量上，於節理面H0H joint與H45Hjoint的右段會增加，垂直向節理H90H joint則增加最少；(6)在雙孔同時受熱狀況下，節理錯動及張開量皆以平行向節理H0H joint最為明顯、H45H joint次之、對垂直向節理H90H joint影響則最小。

關鍵字

處置孔； PFC ；力學耦合；熱-力耦合；平滑節理模型

並列摘要

It is planned to use the PFC (Particle Flow Code) program to simulate the rock pillar between the dual-deposition holes under the condition of intact rock or joints at different angles, due to the mechanical couple of the excavation stress adjustment, and the rock microcracks development under the action of thermal stress and thermo-mechanical couple. First of all, (1) using the uniaxial compressive strength (UCS) test and direct tension test to analyze the micro-mechanical parameters used in PFC in order to understand the influence of micro-parameters on the macroscopic response of the numerical simulation of rock samples, and conducts the training and numerical correction of the input parameters for the mechanical properties of Kinmen granite summarized in the past, and obtain a set of qualified parameters. (2) For joints at different angles, single-hole excavation is carried out in stages to explore the mechanical couple behavior of the rock pillars between the dual-deposition holes, as well as the shear movement and opening behavior of the joint. (3) After the excavation is completed, the shear movement of the hole wall is heated in stages and simultaneously to discuss the rock mass damage and joint shear movement caused by thermo-mechanical couple. The main conclusions of this paper are as follows: (1) The microscopic influencing factors of UCS are parallel bond tensile strength (pb_ten), parallel bond cohesion (pb_coh), and stiffness ratio (k_n/k_s). (2) Excavation of the left hole causes the largest amount of opening in the vertical joint (H90H joint), and the largest amount of shear movement in the H45H joint. (3) After the dual-deposition holes excavation is completed, the opening of the joint surface center in the parallel joint (H0H joint) and vertical joint (H90H joint) is larger than that of joint tips. (4) After the left hole is heated first, the shear movement is most obvious in the parallel joint (H0H joint), In terms of the joint opening, the left and center positions of the parallel joint (H0H joint) gradually increase after heating, and the center position of the H45H joint increases more obviously, the vertical joint (H90H joint) will close after being heated. (5) Next, the right hole is heated. The shear movement is more obvious in the parallel joint (H0H joint) and the H45H joint. In terms of joint opening, the right section of the H0H joint and H45H joint will increase, and the vertical joint (H90H joint) will increase least. (6) Under the simultaneous heating of the dual-deposition holes, the shear movement and opening are the most obvious in the H0H joint, the H45H joint is the second, and the H90H joint has the least influence.