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宁波市地下空间开发利用地质环境制约因素研究   总被引:1,自引:0,他引:1  
地质环境条件是制约地下空间开发利用的最基本因素,只有正确认识地下空间开发对地质环境的影响,才能避免地下空间利用中产生的各种不利后果。基于对宁波市地质环境背景条件的认识,分别从水文地质条件、工程地质条件和环境地质问题等三个方面,研究了地下空间开发利用的影响因素。研究结果表明,水文地质条件的制约因素有孔隙潜水位埋深、含水层厚度、岩土层透水性能和基坑突涌可能性等;工程地质条件的制约因素有软土厚度、人工填土厚度、土质均匀性和地层组合等;主要环境地质问题为地面沉降和浅层天然气影响等。通过本次研究,为宁波市地下空间开发利用地质环境适宜性评价奠定了基础,为宁波市地下空间的合理开发利用提供了技术支撑。  相似文献   
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扩建网极大验后估计模型蕴含联系参数X2和扩建网观测量L2两个方差分量。将联系参数分解成函数不独立部分和函数独立部分,根据限制条件求出函数不独立部分代入扩建网观测方程消去不独立部分联系参数,推导了联系参数函数不独立扩建网极大验后估计的Helmert型、Welsch型和Forstner型方差分量估计。  相似文献   
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Engaging stakeholders in Great Barrier Reef climate change reduction and mitigation strategies is central to efforts aimed at reducing human impacts on the reef and increasing its resilience to climate change. We developed a theoretical framework to investigate subjective and objective constraints on cognitive, affective, and behavioural engagement with the Great Barrier Reef climate change issue. A survey of 1623 Australian residents revealed high levels of cognitive and affective engagement with the Great Barrier Reef climate change issue, but that behavioural engagement was limited by objective constraints that intervene between individuals’ desire to become engaged (affective engagement) and their ability to take relevant actions. Individuals were constrained from increasing their engagement with the Great Barrier Reef climate change issue primarily by lack of knowledge about actions they can take, lack of time, and having other priorities. Individuals’ age, gender, education level, income, and place of residence influenced the probability that they would experience these and other specific constraints on engagement. We suggest that future Great Barrier Reef engagement strategies must endeavour to identify specific behaviour that individuals can undertake to help reduce the impact of climate change on the reef, and find ways to help people overcome the constraints they face on engagement in those activities. The theoretical framework we developed should be useful for investigating constraints on engagement with other environmental issues, but further empirical and conceptual work is necessary.  相似文献   
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结合多数平差和主成分估计理论,导出误差方程中含多重共线性关系时求解未知数的公式,并证明主成分估计的解是最小二乘最小范效解。由此,将主成分估计推广到秩亏自由网平差中,导出求解未知多数及其协因数的公式,并据主成分估计演绎出用附有条件的参数平差法求解秩亏自由网的条件方程(基准在达式)。  相似文献   
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滇西北衙金矿床富水岩浆对成矿的制约   总被引:4,自引:2,他引:2  
鲍新尚  和文言  高雪 《岩石学报》2017,33(7):2175-2188
成矿岩浆富水(4%)是形成斑岩型矿床的关键。滇西北衙金矿床是金沙江-哀牢山新生代富碱斑岩成矿带中规模最大的金多金属矿床,目前探明金资源储量超过320吨,伴生的铅锌、银、铜、铁、硫也达到大-中型规模。本文以北衙成矿的二长花岗斑岩中角闪石斑晶和锆石为研究对象,开展岩相学和地球化学研究,厘定成矿岩浆的特征,并探讨富水岩浆对成矿的制约。研究表明,北衙二长花岗斑岩角闪石斑晶发育、轻稀土富集而重稀土亏损、具有高Sr(300×10~(-6))、低Y(10×10~(-6))和高(La/Yb)N(6.19~26.8)的地球化学特征,暗示在岩浆结晶早期有角闪石斑晶的晶出。角闪石晶出的条件是岩浆中水含量大于4.5%,因此北衙金矿床成矿岩浆演化早期角闪石的晶出显示成矿岩浆相对富水。角闪石矿物组分计算表明岩浆熔体中水含量在3.8%~4.1%之间,进一步证实北衙金矿床成矿岩浆相对富水。北衙金矿床这种具有高水含量的岩浆在源区岩石部分熔融的过程中,水的加入可以降低其熔点,促进源区含Cu、Au硫化物重熔,或萃取岩石中Cu、Au成矿元素,或聚集岩浆中分散分布的金属元素,形成富金属、富水的岩浆。含矿岩浆就位后,其通过压力的降低(岩浆房脆性破裂或岩浆向上侵位)来降低水的溶解度,或通过岩浆持续的结晶(在等压条件下晶出无水矿物)逐渐提高岩浆水含量,促使熔体中水含量大于水在熔体中溶解度,从而导致岩浆水达到饱和状态,流体开始出溶。总体而言,北衙金矿床富水岩浆不仅能促进北衙矿床成矿流体的形成与演化,也对成矿流体中Cu、Au等成矿元素的富集具有重要的作用。  相似文献   
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重磁异常三维物性反演随机子域法方法技术   总被引:17,自引:6,他引:17       下载免费PDF全文
本研究针对三维物性反演中存在的困难和问题,提出三维物性反演的随机子域方法技术,首先是将正反演中保持不变的几何格架分离计算并存储,避免重复计算,从而提高正反演计算速度;其次是利用对称性等实现等效计算,明显降低格架计算和存储要求;再通过随机子域方式,降低反演的维数问题;另外,通过概率方式控制子域生成的分布,实现约束新机制. 模型和实例计算表明了方法技术的效果,为大面积重磁数据的三维反演提供了有效的途径.  相似文献   
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山谷型风景区内的地质灾害治理难度较大,主要是为了最大程度地保护风景区的自然景观与自然资源,其次是由于景区内往往没有宽大的混凝土主路,仅有崎岖小路,治理工作所需的材料及设备运输全靠人工完成,无法采用大型机械设备进行施工,因此,最终的治理方法受到很大限制。根据2015年在云蒙山风景区(南段)开展的地质灾害调查及治理设计工作成果,本文重点介绍危岩体(带)的地质灾害特征及治理措施,并对山谷型自然风景区内的危岩体(带)地质灾害治理措施的合理选择进行探讨。  相似文献   
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The changes of development and utilization of karst groundwater in Sangu Spring Basin have made the original groundwater resource evaluation unable to meet the needs of future economic development. Based on analysis of existing data, combined with the characteristics of supplement, runoff and draining of regional karst groundwater, the Visual Modelflow software was used to build a numerical simulation model of Sangu spring Basin. The amount of karst groundwater resource and groundwater environment of the Basin were evaluated under different exploitation schemes, and the changes of karst groundwater environment in the future ten years were also predicted. The fitting error which is less than 0.5 m between the calculated value and measured value of the water level in the fitted borehole accounts for 93%. For the lithologically and structurally complex Sangu Spring Basin, the fitting effect of numerical simulation model was ideal. On the basis of the current mining amount of 111.80 million m3/a, the total redistributed exploited amount in the spring region was 61.79 million m3/a. Under the condition that the quantity of recoverable resources reached 173.59 million m3/a and under different precipitation schemes, all constraint conditions were satisfied, such as regional water level drawdown, maximum allowable water level drawdown in every simulated water source area and the flow rate of Guobi Spring. The results will provide a scientific basis for the rational development and utilization of karst groundwater in Sangu Spring Basin.  相似文献   
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