大型帐篷构造对贵州天星桥喀斯特石林形成演化的控制作用

贵州黄果树天星桥景区下三叠统安顺组白云岩广泛出露,分布有连片水上石林,其发育在下三叠世台地相与深海盆地过渡的台地边缘相带上,这里海水进退频繁,古海岸带暴露面上大型帐蓬构造十分发育.碳酸盐岩古暴露带这种岩性特征,一则导致岩石充满裂隙及孔洞,极有利于大气降水入渗及地下水的赋存和运移;另则导致岩体软弱结构面密布,岩石的力学强...     

Introduction to dynamics of stone arches

The dynamic analysis of stone arches, made up of rigid voussoir laid dray, can be performed in two phases. First of all the value of the horizontal acceleration necessary to turn the structure into a mechanism and the corresponding mechanism must be determined. Then the dynamic behaviour of such a mechanism under a given acceleration time history can be studied. The first step is a static matter. The second one requires the solution of the non-linear equation of motion of the one-degree-of-freedom system in which the arch is turned. In this paper an iteration procedure is proposed to find out the mechanism. Then the structural behaviour of the mechanism is analysed. Both free and forced vibrations are investigated and the study is limited to the first-half cycle of vibration. Damping is not considered and sliding between the blocks at the hinge sections is not allowed. © 1998 John Wiley & Sons, Ltd.     

四川长宁石林地质遗迹景观资源特征及开发建议

长宁石林地质遗迹景观资源丰富,类型多样。最具代表性的景观资源是岩溶地貌,有溶洞、石林、天坑、漏斗、地缝、暗河、瀑布等,并有其他多种配套景观资源。这些地质景观资源具有重要的地学科研和美学观赏价值,具有较大的开发潜力。     

对一种振冲碎石桩复合地基沉降计算方法——Priebe法的改进

通过对经典的Priebe沉降计算法分析,以及面积置换率的变化对桩体压缩性假设作了改进;对桩土重度差异及承受荷载时应力和变形与深度的关系作了分析,归纳出相应的数学计算公式,用工程实例进行了验证。得到的结果表明改进是合理、适用的,可为今后的设计和施工提供参考。     

土石混合体分形几何特征与强度演化特征

针对土石混合体的结构性特点,以含石量为20%、30%、40%、50%、60%的土石混合体为研究对象,基于多重分形原理研究多重分形特征,研究分形维数与强度之间的关系。研究表明,土石混合体具有双重分形特征,不同尺度条件下具有不同分形指标,包括块石粒度、土体粒度以及平均粒度等分形维数,与含石量相关。单轴压缩试验表明,抗压强度随含石量增加呈现先增大后减小的趋势,根据单维分形特征,确定最优含石量约为40%。建立了含石量、不同分形维数指标与抗压强度之间的关系,分析了双重因素综合影响下抗压强度的变化特征,确定了含石量与分形维数之间存在最优区域。     

Calcified roasting-acid leaching process of vanadium from low-grade vanadium-containing stone coal

The low-grade vanadium-containing stone coal used in this experiment was collected from Wuxi Coun- try, Chongqing City, China. The experiment focused on the vanadium recovery from roasted residue through opti- mizing the process conditions of an effective and environmentally-friendly technology, named calcified roast- ing-sulfuric acid leaching technology. By single-factor experiments and orthogonal experiments, the effects of roast- ing temperature, roasting time, sulfuric acid concentration and leaching time on the leaching ratio of vanadium were analyzed. The results showed that the leaching ratio of vanadium reached 85.5% under the proper technological con- ditions of roasting temperature=950℃, roasting time=4 h, 40% concentration of sulfuric acid and leaching time=6 h.     

湖北清江画面石图案的纹理类型及其地质成因

清江画面石是近二十年来出现的一种新的观赏石石种,原石主要为中泥盆统云台观组灰白色石英砂岩.清江画面石具有观赏价值的关键因素是构成画面的各类图案.本文将画面石图案的纹理类型划分为三种类型——线型、条带型和梳型,并对每种类型进行了详细描述.在野外调查基础上,通过岩石特征、微观结构构造、地球化学特征等综合对比分析,对三种类型的清江画面石图案的地质成因进行初步讨论,认为线型（即裂隙）的形成可能与燕山期或之后区域构造活动有关,条带型（即层理）形成于泥盆纪的原生沉积构造,而梳型则可能是由于外来物质在成岩期后沿着层理面或纹层面向下渗流而成,推测形成于燕山期之前,但需进一步研究确定.三种图案中的不同颜色,是由含有铁锰质氧化物的地下水或地表径流水等沿裂隙、层理面或渗流面浸染或部分交代填隙物而成,在现代河流下切作用下,崩落入水,经过流水搬运、冲刷,最终形成了清江画面石.     

浅谈清江观赏石的岩性特征及颜色成因

本文在前人资料的基础上,结合多年奇石开发利用和实地考察经验,介绍了清江观赏石的分类与特点,归纳总结了其形成的地质背景及岩性特征,并从铁质来源与填充、浓度变化和气候周期影响等几个方面分析了清江观赏石的颜色成因。     

一种红色砭石的矿物学特征研究

采用X射线粉末衍射（XRD）、扫描电子显微镜（SEM）、热重分析（TG-DTG）及激光诱导离解光谱（LIBS）等分析方法对一种红色砭石的矿物学特征进行了深入的研究。XRD分析表明,红色砭石主要由白云石组成,并含有少量石英和方解石及微量云母、正长石和赤铁矿。SEM结果显示,砭石中的矿物颗粒大多为集合体,粒径大多集中在1～5μm之间,表面光滑程度有所不同。红色砭石在650-850℃范围内出现一个单失重峰,为白云石的分解形成,类质同象或者杂质矿物的存在导致白云石两阶段的分解同步完成。红色砭石的颜色可能与赤铁矿和正长石微晶在砭石中的均匀分布有关。     

Aggregate resources: Production and environmental constraints

Aggregates are produced from sand and gravel deposits or from bedrock sources. Production sites are numerous to minimize transport and are more and more in a competing land use position. Urbanization, while creating a market, also sterilizes deposits and pressures producers to relocate further from populated areas. Regulating and permitting quarries is an issue in regions with growing populations. This regulatory environment may cause exploitation schemes to evolve towards greater recycling, importing, and marine production, for example. These changes may be entirely attributable to increased environmental constraints on producing operations and not on conventional mining constraints such as overburden, ore grade, and costs of operation.