Permeability and Energy Evolution Characteristics of Heterogeneous Coal and Rock Mass

Natural Resources Research - The coupling characteristics of stress, fracture, and seepage fields are significant to gas extraction and water-preserved mining. In this paper, a theoretical model...     

Experimental study on the influence of hydro-chemical erosion on morphology parameters and shear properties of limestone fractures

Acta Geotechnica - Hydro-chemical erosion has a great effect on the micro-structure morphology and macroscopic mechanical properties of the rock mass. In this paper, direct shear test system was...     

Physical simulation research on evolution laws of clay aquifuge stability during slice mining

The aquifuge stability is the key to study the impacts of coal mining on the aquifer. Based on the geological conditions of a mine in Yili of Xinjiang, China, this paper has studied the stability evolution laws of clay aquifuge during extremely thick coal seam mining by similar material simulation experiment in the laboratory. For the water-swelling and expansion property of clay aquifuge, the reasonable proportion of the similar material is firstly determined by taking the uniaxial compressive strength and the permeability coefficient as core indexes. Then, the overlying strata movement coupled solid–liquid physical model is established. In addition, the aquifuge deformation, the water level changes of the aquifer, and the height of fracture zone in overburden are analyzed during the slice mining. The research results indicate that the clay aquifuge will gradually occur instability failure during the mining of the working face, and the aquifuge stability has the threshold effects. When the ratio of the vertical displacement of the aquifuge to the thickness is D_v/T?≤?58.0%, the ratio of the horizontal displacement to the thickness is D_h/T?≤?17.0%, and the height of fractured zone in overburden is below the aquifuge, the mining-induced fractures may be closed and the aquifuge stability could be maintained. If D_v/T?≥?75.0%, D_h/T?≥?23.9%, and the height of fractured zone in overburden is within the aquifuge, the fractures will develop and connect the aquifuge and the stability failure of the aquifuge will occur, which has a direct correlation with the mining height.     

大兴安岭北段奇力滨地区玛尼吐组火山岩年代学、地球化学特征及其构造意义

大兴安岭北段奇力滨地区玛尼吐组火山岩主要为粗面安山岩和粗面岩.LA-ICP-MS锆石U-Pb年龄为142.2～141 Ma,表明火山岩形成于早白垩世.岩石地球化学结果表明,奇力滨地区玛尼吐组火山岩SiO2含量介于54.09％～64.89％之间,具有高铝 Al2O3(14.67％～17.27％)、高全碱 K2O+Na2O(6.33％～8.74％),较低的MgO(0.81％～2.71％)和Mg#(24.84～46.15),为高钾钙碱性火山岩;稀土总量(∑REE)介于146.51×10-6～193.29×10-6之间,轻重稀土分馏明显(La/Yb)N=8.5～15.52,弱的负铀异常(δEu=0.64～0.96);微量元素以富集Rb、Ba、K等大离子亲石元素(LILE)和轻稀土元素(LREE),亏损Ta、Nb、Ti、Zr、P等高场强元素(HFSE)为特征,同时具有Hf正异常和高Th/Ta、Th/Nb比值,较低的Lu/Yb(0.14～0.16)和Rb/Sr(0.02～0.17)比值.结合前人研究成果,本研究认为奇力滨地区玛尼吐组火山岩岩浆源区为俯冲消减板片流体交代的地幔楔部分熔融,在岩浆上升过程中经历了分离结晶作用和浅部地壳物质的同化混染.该区火山岩形成与蒙古-鄂霍茨克洋闭合造山后的岩石圈伸展和软流圈上隆作用有关.