Utilizing information from plate tectonics characteristics, volcanic activities, and geothermal anomaly, this paper identifies areas where hot dry rock (HDR) may exist as potential geothermal resource in China. Further investigations are also carried out in the paper based on results from regional tectonics, volcanic geology and lithology, as well as data from geothermal displays, geochemistry, geophysics, and shallow borehole temperature measurements. The study reveals several promising areas of HDR geothermal resource in China, including Tengchong of Yunnan province, Qiongbei of Hainan province, Changbaishan of Jilin province, Wudalianchi of Heilongjiang province, and the Southern Tibet area. A 3D static heat conduction model was developed to study the underground temperature gradient characteristics of the Rehai geothermal field in Tengchong and the Yangbajing geothermal field in Tibet. The model adopted is a geological block 10 km deep from the ground surface and 50 km wide in each of the horizontal directions (2500 km2 area). The numerical simulation results in evaluations on the quantities of the HDR geothermal resource in Rehai and Yangbajing geothermal fields. The paper shows that there is abundant HDR geothermal resource with large exploitation value in China. If developed with a power capacity of 1!108 kW, the Rehai and Yangbajing fields along would be able to generate electricity for 1560 years.

A great deal of data obtained from production practice indicates that in medium-hard seams and softer seams the resistance of rear leg is smaller than that of front leg in a sublevel caving powered support. When caving the top-coal, the resistances of both front leg and rear leg decrease, but the resistance of front leg decreases more than that of rear leg. In some cases, the resistance of rear leg even rapidly lowers to zero. This will seriously bring bad influence to making full use of the load-carrying capacity of the support, and damage the relation between support and surrounding rocks. So that to damage the control of the surrounding rocks of the face. The theory analysis points out that because the top-coal closed the gob is very fragmentized, lowering of the stiffness brings lowering of the load-carrying capacity, so the support’s acting point of the load moves frontward and thus the resistance of the rear leg is smaller than that of the front leg. Because of the top-coal’s further fracturing and moving the fact becomes more serious when top-coal is caving. The extreme case is that the resistance of the rear leg decreases to zero. Based on the theory analysis, the paper presented some measures to improve the load-bearing condition of the support. For example, changing the structure of the powered support and not caving too much top-coal, etc.

针对浙江长广七矿埋深近千米，地质条件极其复杂的回采巷道支护问题，在数值模拟研究巷道围岩变形机理的基础上，设计了斜顶鼓梯形巷道断面，确定了高强度锚杆支护参数并用于现场施工。现场观测表明，锚杆支护使巷道围岩得到有效控制，巷道表面变形大大下降，取得了良好的围岩控制效果。

高温岩体地热开发及核废料的地下处置等需要对高温高压下花岗岩体的力学行为进行深入细致研究。采用自主研制的“20 MN伺服控制高温高压岩体三轴试验机”，投入大量人力、财力和物力，历时0.5 a，系统深入地研究φ 200 mm×400 mm的大尺寸花岗岩试样在高温三轴应力下的热变形和破坏特征及其热学和力学参数随温度的变化特征。研究结果表明：(1) 在三维静水应力下，花岗岩的热变形可分为低温缓慢变形段、中高温快速变形段及高温平缓变形段等3个阶段，自由状态测定的热膨胀系数会过分夸大，或失真地估计岩石的热膨胀或热力作用，在应力状态下测定的热膨胀系数更能反映实际岩体状态；(2) 在高温三轴应力条件下，花岗岩体受压表现出与常温下不一致的变形特征，即先是体积膨胀，当差应力超过一定值后则体积收缩；(3) 花岗岩体在高温下的破坏形式是典型的剪切破坏，与常温下的破坏形式一致，但在高温和高围压条件下出现明显的延性转化；(4) 在有围压条件下，花岗岩体的弹性模量随温度升高先是缓慢减小，然后快速减小，超过400 ℃后基本保持不变，与小试件的情况相似。

Qiongbei volcanic area of Hainan Province has apparent resource, economy and geography dominance in hot dry rock (HDR) geothermal resource extraction, which does not exist in other areas in China. So the authors presented a bold primary conception of HDR extraction system project in this paper. The project contains boring design, artificial reservoir design, interval distance design of different cycling well units, geothermal resource quantity estimate of single cycling well unit and design of appropriate installed capacity and service life. The paper also gave an investment analysis according to MIT Economic Model of HDR extraction. The preliminary cost-effectiveness analysis indicates that Qiongbei volcanic area of Hainan is an ideal preferred place to start a demonstrational project of HDR geothermal extraction in China.