Flow of Hydrothermal Solution in the Crust and Mechanism of Rock Alteration

开发了干热岩体多裂隙水岩作用模拟器。提出了用具有温度梯度的流动式压热器预测干热岩石因裂纹变形而排热寿命的可能性。此外，在静态和流动条件下，岩石粉末的石化进行了研究。在静态条件下，粉末的机械压缩容易发生石化。通过对菱狩金矿区天然裂隙的观察和矿物沉积年代学计算，证实了裂隙的分布符合分形理论，天然脉是矿物沉积间断重复形成的。在热-干岩石中人工产生的用于取热的裂缝在水-岩相互作用下被预测为管状。提出了一种通过堵塞管道裂纹来产生新裂纹控制排热的新方法。在水热条件下，通过由硅酸镁锂组成的浆料穿过裂缝，导致裂缝中的蒙皂石族粘土矿物固化。研制了一种用于水热条件下测量溶液通过裂缝时pH值的传感器。通过与理论热力学计算的比较，证实了该传感器测量pH值的准确性。从电化学角度对溶解-沉积过程进行了探讨，证实了金属氧化物和氢氧化物反应生成络合物导致沉积，而存款对岩石基质的力学性质有很大影响，研究结果为实际开采热岩提供了控制干热岩石多裂纹的方法。本研究所设计的实验装置可应用于地球化学、环境科学、材料科学等领域。

The simulator of water-rock interaction among multi-cracks in hot-dry rock has been developed. The possibility to predict the lifetime of heat extraction from hot-dry rock due to deformation of cracks was proposed by using flow type autoclave with temperature gradient. Besides, lithification of rock powders was investigated under static and flow conditions. Lithification easily occurred under static conditions with mechanical compression of the powders. It was confirmed by observation of the natural fractures in Hishikari-gold mine and the chronological calculation of deposited minerals that the distribution of the fractures agreed with fractal theory and the natural veins were formed by intermittent repeat of mineral deposition. Cracks artificially produced in hot-dry rock for heat extraction are predicted to be tubular in shape by water-rock interaction. A new method to produce fresh cracks for controlling heat extraction was developed by blocking the tubular cracks. Passing slurry consisting of lithium magnesium silicate through the cracks under hydrothermal conditions, resulted in solidification of smectite group clay minerals in the cracks. A sensor was developed to measure pH of solutions passing through cracks under hydrothermal conditions. The accuracy of pH measured by the sensor was confirmed by comparison with theoretical thermodynamic calculation. Discussion on dissolution-deposition process from electrochemical aspect confirmed that complex formation by reaction of metal oxides and hydroxides caused deposition and the deposit had a large effect on mechanical properties of the rock matrix.The results obtained by this research gave the method to control the multi-cracks in hot-dry rocks for practical heat extraction of generate. The facilities designed in this research are useful for many area of researches such as geochemistry, environmental science, and materials science.