摘 要 近年来，随着我国煤炭开采不断向西部、向深井发展，在陕西、甘肃、内蒙古及新疆等西部地区已掀起矿井建设的新高潮。而这些地区煤田覆盖着大量的白垩系地层，其具有富含水、低强度、弱胶结、遇水泥化等特点，冻结法因在含水地层中的支护范围和支护深度上的独特优势，已成为井筒穿越深厚富水基岩最有效的施工方法之一。进行冻结白垩系地层砂岩的物理力学特性研究，可为西部矿井冻结设计和稳定性研究提供基础参数，也对丰富我国岩土力学的基础理论起到积极作用。 本文以华能甘肃新庄煤矿风立井冻结工程为背景，对井筒穿越的代表性白垩系富水地层岩石的物理力学特性进行研究。论文首先分析了西部白垩系地层特征、地质构造及水文地质等特性，采用扫描电镜（SEM）观察了白垩系砂岩的微观结构特征，试验研究了砂岩的物理参数及变化，从宏微观角度系统分析了白垩系岩层的特殊性；深入研究了不同含水状态、不同低温条件下两种砂岩的导热系数等热物理性质，探讨了白垩系砂岩热物性的影响因素及规律；对不同低温下白垩系砂岩的单轴强度特性，不同低温、不同围压下的三轴强度特性进行了系统研究，得到冻结白垩系砂岩单轴、三轴抗压强度与温度的关系表达式；全面分析了冻结白垩系砂岩的全应力-应变曲线及轴向、体积应变等变形规律，重点探讨了岩石的弹性模量、泊松比与温度的相关性，最后分析了白垩系砂岩的变形破坏过程和破坏形式。 试验结果表明，白垩系砂岩具有含水丰富、孔隙度高、泥质胶结及遇水软（泥）化等特点；不同含水、不同低温下，两种白垩系砂岩的热物性变化差异性较大；饱和岩石的单轴抗压强度随着温度的降低而增大，且粗砂岩的强度总是大于中砂岩；温度越低、围压越大，白垩系砂岩的三轴抗压强度越大；岩石的变形经历了孔隙压密、弹性、塑性变形和应变软化四个阶段；随温度的降低，弹性模量不断增大、泊松比却不断减小，说明冻结岩石的塑性减弱、脆性增强；白垩系砂岩的单轴破坏以张拉破坏的形式为主。

ABSTRACT In recent years，with the process of coal exploitation in China gradually develop to the west and deep well, there has a climax of the new wells construction in Shaanxi, Gansu, Inner Mongolia, Xinjiang and other western regions. And the region coal field is covered with a mass of cretaceous strata, which has characteristics of rich water, low strength, weak cementation, argillization, etc. Freezing method has unique advantages for support scope and depth in water-bearing strata, already become one of the most effective special construction methods for shaft to across the deep bedrock. To experimental study on the characteristic of physics and mechanics of freeze cretaceous sandstone, which will provide basis parameters for the west mine freezing design and stability study, and also play a positive role in enriching our country theory of rock and soil mechanics. The article was based on the background of xinzhuang coal mine shaft freezing wind project in Gansu province, made a comprehensive study to the physical and mechanical property of representative cretaceous rich water strata rocks when the shaft through. First, analyzed western cretaceous strata characteristics, geological structure and hydrological geology characteristics, observed the microstructure characteristics of sandstones by scanning electron microscopy (SEM), experimental studied on the characteristics of conventional physical parameters of sandstones, systematic analysed the particularity of cretaceous strata from macro to micro; in-depth analysed the thermal physical properties of sandstones under different moisture state and different low temperature, and its influencing factors;system researched uniaxial mechanical characteristics of cretaceous sandstones with different low temperature, fitted for the relationship between uniaxial or triaxial compressive strength of frozen rock and temperature; comprehensive analysed of the whole stress-strain curve and deformation rule which conclude axial and volumetric strain of freeze cretaceous sandstones, emphasis discussed the correlation between elasticity modulus and poisson ratio of rocks with temperature. Finally, expounded the deformation and failure process of cretaceous rocks and destruction form. The result shows, characteristics of cretaceous sandstones are water-rich, macropore, argillace- ous cementation and small frozen deformation. The difference of thermophysical property of two cretaceous sandstones is large, under different water content and low temperature. The uniaxial compressive strength of saturated rock is increasing with low temperature, and the strength of gritstone is always greater than medium sandstone. The lower temperature and the larger confining pressure, the greater triaxial compressive strength of cretaceous rock.The deformation of frozen rock experienced four stages conclude pore compaction, elastic and plastic deformation and strain softening. With the decrease of temperature, elastic modulus is increasing, poisson's ratio is reducing, account for plastic of frozen rock is abating, brittleness is increasing, and the main damaging form of cretaceous rocks is tension damage.