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选取高放射核废物处置库重要预选场区甘肃北山地区的花岗岩,制作750 mm(宽)×300 mm(厚)×1 000 mm(高)的稀疏不规则裂隙岩体模型,该模型由18块花岗岩和竖向与斜向各两条裂隙组成,在裂隙及岩石内部埋置温度传感器、水压计、直角应变花,并在模型一侧设置局部热源,研究热源温度和裂隙水流速对岩石温度和应力的影响。结果表明,竖裂隙水主要从顶部进水口流向底部出水口,斜裂隙水主要从侧部进水口流向侧部出水口,竖裂隙与斜裂隙在交汇处存在微小流量交换;由于热源处在两条斜裂隙进水口之间,并且斜裂隙长度小于竖裂隙,岩石热传导与斜裂隙水流对岩石温度分布起控制作用,竖裂隙水流对岩石横向热传导起阻滞作用;由于热传导和水流传热的不规则性,上层岩石形成从左向右为主的传热路径,中层和下层岩石形成从上向下为主的传热路径;由于上、下层岩石温度梯度较小,岩石收缩受热拉应力,而中层岩石温度梯度较大,岩石膨胀受热压应力,大主应力的方向大致垂直于斜裂隙面与竖裂隙面的交线,岩石应力增量随斜平面方向的温度梯度增大而增大;热源温度越高,裂隙水流速越低,岩石温度越高、岩石应力越大,系统达到稳态需要的时间越长。
Select the granite in the Beishan area of Gansu, an important preselected field for high-level radiation nuclear waste repository, and make a sparse irregular fractured rock mass model of 750 mm (width) × 300 mm (thickness) × 1 000 mm (height) Granite and two vertical and diagonal fractures. Temperature sensors, piezometers and right-angle strain flowers were buried in the cracks and rocks. Local heat sources were set on the model side to study the influence of heat source temperature and fissure water flow rate on rock temperature And the impact of stress. The results show that the vertical fissure water flows from the top inlet to the bottom outlet, and the diagonal fissure water flows from the side inlet to the side outlet, and there is a slight flow exchange between the vertical fissure and the oblique fissure at the confluence. Since the heat source is in two The oblique fissure inlet is smaller than the vertical fissure. The rock heat conduction and oblique fissure water flow control the rock temperature distribution. The vertical fissure flow has a retardation effect on the rock lateral heat conduction. Due to the irregularity of heat conduction and water flow The upper and lower rocks form a left-to-right-oriented heat transfer path. The middle and lower rocks form a heat transfer path mainly from top to bottom. Because the temperature gradient of the upper and lower rocks is small, the shrinkage of the rock is heated and tensile, while the middle The rock temperature gradient is larger and the rock is expanded and compressively stressed. The direction of the principal stress is roughly perpendicular to the intersection between the oblique fracture surface and the vertical fracture surface. The rock stress increment increases with the temperature gradient along the oblique plane. The higher the temperature, the lower the fissure water flow rate, the higher the rock temperature, the greater the rock stress and the longer the system needs to reach steady state.