对人造地震动反应谱求解及拟合的几个相关问题探讨

为更高效合理地生成与设计反应谱相符的人造地震动信号,本文基于自主开发的地震动信号处理软件EQSignal对人造地震动生成过程中涉及的几个问题进行了探讨,并通过对单自由度简谐共振体系的响应分析,提出了具体的解决建议:① 反应谱求解时应该对高频段和低频段分别采用频域传递函数法和逐步积分法求解;② 反应谱周期控制点的分布模式也应分段处理,短周期段宜采用对数平均分布,长周期段宜采用线性平均分布,反应谱总周期控制点不宜少于120个;③ 人造地震动反应谱与设计反应谱拟合的过程中,使用频域方法与时域方法相结合可兼顾效率与收敛性。      

组合核支持向量回归提取高光谱影像不透水面

由于城市地表组成的复杂性,基于单核函数的支持向量回归模型很难满足精度。本文结合空间-光谱组合核函数和支持向量回归,提出了一种提取高光谱影像不透水面丰度的改进算法。首先从高光谱遥感图像上提取波谱特征和多通道灰度共生矩阵空间纹理特征,选取研究区10%像元特征数据作为训练数据,以线性加权求和核为多核组合方式,建立结合光谱信息和空间信息的组合核支持向量回归模型。然后,用生成的回归模型预测未知像元不透水面丰度值。最后,对实验结果进行评价。在模拟数据试验中,本文算法比单核回归均方根误差平均降低1.4%,决定系数比单核回归平均提高0.6%。在Hyperion数据两组试验中,该算法比单核回归均方根误差平均降低1.8%,决定系数比单核回归平均提高11.7%。模拟和真实两种高光谱数据实验中,本文算法均得到了空间形态上更准确的不透水面结果,单核回归结果存在失真现象。研究结果表明:本文算法能够有效提取城市不透水面丰度,与单核方法相比有较明显的精度提升。     

埕宁隆起区寒武系—奥陶系岩溶热储资源评价

为进一步探究山东埕宁隆起区域内热储资源量,制定合理可持续的开发方案,为地热资源的进一步勘探和综合开发提供科学依据,本次研究结合野外地质调查测试结果及以往成果资料,分析了区内地热流体成因,并采用热储法与综合指数法,对寒武系—奥陶系岩溶热储进行资源量估算及开发前景分析。结果表明：区内寒武系—奥陶系岩溶热储可利用地热资源量为1.97×10¹⁹ J,折合标准煤6.72×10⁸ t;地热流体年均可采量为29 777.40万m³/a;具备未来开采条件的区域面积为1 538.29 km²,占岩溶热储总面积的86.18%。区内寒武系—奥陶系岩溶热储具有较高的开发利用潜力,应加大勘查力度,推进开发利用进程。     

Study on frost heaving characteristics of sandstone under different freezing conditions北大核心CSCD

At present,artificial freezing method has become one of the effective methods for coal mine shaft to pass through water-rich soft rock strata,which can stop the movement of groundwater and limit the deformation of surrounding rock. In order to study the frost heaving characteristics of sandstone under different freezing conditions,frost heaving tests of saturated and dry Cretaceous red sandstone samples under different freezing rates （10 ℃·h-1,5 ℃·h-1,2 ℃·h-1,1 ℃·h-1）and different confining pressures（5 MPa,10 MPa,15 MPa,20 MPa,25 MPa）were carried out by using GCTS（Geotechnical Consulting & Testing Systems）servo-controlled low temperature and high pressure triaxial rock testing system. In this paper,based on the existing theory of physical and mechanical properties of frozen soil,we studied the frost heaving law of sandstone under different freezing conditions and explored the frost heaving mechanism. The result shows that in the process of cooling,the dry rock sample always produce cold shrinkage deformation,while the saturated rock sample first produce cold shrinkage deformation,then produce frost deformation,and finally the deformation tends to be stable. The deformation of saturated rock samples is much larger than that of dry rock samples. The larger the stress level of rock samples at the same temperature is,the smaller the frost deformation is,which shows a linear negative correlation,mainly because the high confining pressure limits the volume expansion of the water phase in the pore inside the rock samples when it becomes ice. The frost deformation of rock samples is mainly affected by confining pressure and water content,while the frost heaving rate is mainly affected by cooling rate. Under this test condition,the higher the cooling rate of sandstone is,the higher the frost heaving rate is,and the relationship between them is approximately linear. For saturated rock samples,the confining pressure reduces the rock frost heaving by limiting the expansion during the phase transformation of ice water,and the temperature affects the rock frost heaving by affecting the freezing rate of pore water and the thermal expansion and cold contraction of rock skeleton. For dry rock samples,the deformation is mainly due to the volume contraction of rock mineral particles caused by thermal expansion and cold contraction effect,and the greater the temperature change,the greater the deformation. Based on the experimental results and theoretical analysis method,a calculation formula of rock frost heaving considering the influence of confining pressure was established. By calculating the frost heave of sandstone samples under different confining pressures,it is found that the calculated values are in good agreement with the experimental results. Moreover,according to the calculation formula of frost heaving,the influence factors of rock frost heaving during freezing can be divided into two categories：internal cause and external cause. The internal cause includes porosity,saturation,volume modulus of ice and rock skeleton,and the external cause includes temperature and confining pressure. For saturated rock,the frost heaving is mainly affected by factors such as confining pressure,temperature and porosity. When the saturation,porosity and freezing rate are low,the rock may only produce shrinkage deformation,because these indicators determine whether the rock produces frost heave or freeze shrinkage. The mechanism of rock frost heaving is very complicated due to the interaction and restriction between the internal and external factors and the dynamic changes of rock micro-structure and mechanical properties during the process of frost heaving. The research results can provide theoretical reference for freezing construction scheme design of deep coal seam mine construction,and also provide a theoretical basis for the study of physical and mechanical properties and engineering application of soft rock in frozen soil area. © 2022 Science Press (China).     

基于信息量、加权信息量与逻辑回归耦合模型的云南罗平县崩滑灾害易发性评价对比分析CSCD

以罗平县崩滑地质灾害为研究对象,选取工程岩组、坡度、坡向、高程、起伏度、曲率、地貌类型、距河流距离、距断裂距离9个评价因子,基于共线性诊断和相关性分析对其进行独立性检验。然后采用信息量法计算各评价因子分类分级的信息量值,采用层次分析法和逻辑回归法对各评价因子进行权重的定量计算,从而构建信息量、加权信息量和信息量-逻辑回归耦合易发性评价模型并进行对比分析。基于GIS的自然断点法将评价结果划分为非、低、中和高4个等级,并采用ROC曲线对其精度进行检验。结果表明:3种评价模型的AUC值分别为0.757、0.723和0.852,信息量-逻辑回归耦合模型的精度最高,模型结果分区与崩滑地质灾害点的分布较吻合,其非、低、中和高的面积(分级比)分别为771.1 km^(2)(25.55%)、836.6 km^(2)(27.73%)、864.36 km^(2)(28.64%)和545.94 km^(2)(18.08%)。     

基于信息量、加权信息量与逻辑回归耦合模型的云南罗平县崩滑灾害易发性评价对比分析CSCD

以罗平县崩滑地质灾害为研究对象,选取工程岩组、坡度、坡向、高程、起伏度、曲率、地貌类型、距河流距离、距断裂距离9个评价因子,基于共线性诊断和相关性分析对其进行独立性检验。然后采用信息量法计算各评价因子分类分级的信息量值,采用层次分析法和逻辑回归法对各评价因子进行权重的定量计算,从而构建信息量、加权信息量和信息量-逻辑回归耦合易发性评价模型并进行对比分析。基于GIS的自然断点法将评价结果划分为非、低、中和高4个等级,并采用ROC曲线对其精度进行检验。结果表明:3种评价模型的AUC值分别为0.757、0.723和0.852,信息量-逻辑回归耦合模型的精度最高,模型结果分区与崩滑地质灾害点的分布较吻合,其非、低、中和高的面积(分级比)分别为771.1 km^(2)(25.55%)、836.6 km^(2)(27.73%)、864.36 km^(2)(28.64%)和545.94 km^(2)(18.08%)。     

铀矿区花岗岩锆石定年的“高铀效应”:来自鲁溪和下庄花岗岩SHRIMP锆石U-Pb年龄的启示

下庄铀矿田是我国最重要的花岗岩型铀矿田之一,其中的复式花岗岩体已获得了一批锆石U-Pb年龄,基本上构筑了下庄铀矿田加里东、印支和燕山多期多阶段的岩浆演化系列。分析前人数据发现,不同学者获得的同一岩体的锆石U-Pb年龄差别较大,最大相差达17 Ma,主要原因之一可能是高U锆石的存在导致了加权平均年龄可靠程度的降低。针对这一问题,笔者以下庄铀矿田鲁溪粗粒黑云母花岗岩和下庄中粒黑云母花岗岩为研究对象,采用SHRIMP锆石U-Pb法测试U-Th-Pb含量,重点分析了锆石U含量对²⁰⁶Pb/²³⁸U年龄的影响,并厘定了这两个岩体的侵位年龄。测试结果显示,鲁溪粗粒黑云母花岗岩38颗锆石的U含量变化于152×10^–6～5687×10^–6之间, ²⁰⁶Pb/²³⁸U年龄变化于234～1345 Ma之间,可分为五组,其中年龄最小一组由27颗锆石组成,变化于234～265 Ma之间,加权平均年龄为247.3±3.2 Ma, MSWD=3.9;下庄中粒黑云母花岗岩18颗锆石的U...     

联合时序InSAR和滑坡灾害易发性的元阳县滑坡灾害隐患识别

目前合成孔径雷达干涉(interfermoetic SAR,InSAR)理论与技术一直处于快速发展态势,在地质灾害隐患识别方面已有阶段性的进展,但是为了提高识别的效率与准确度还需进一步的研究。因此提出一种联合时序InSAR(Interfermoetic SAR)技术和滑坡灾害易发性的方法对云阳县进行滑坡灾害早期识别。该方法通过小基线集干涉测量(Small Baseline Subset InSAR, SBAS-InSAR)技术获得该地区地表形变信息,再结合通过信息量模型以地貌类型、土地利用类型、断层距离、高程、工程地质岩组、坡度、坡向、曲率与河流距离9个评价因子作为信息量值获得的滑坡灾害易发性区划与谷歌影像分层次进行潜在滑坡灾害的识别。然后对识别结果进行验证,研究表明了该种方法在此地区应用的可行性,且研究成果为地质灾害进一步的调查提供了参考与技术支持。     

一种基于区块链和边缘计算的物联网方案

物联网设备资源受限,需要使用外部资源,而集中式的云方案恰好可以为物联网提供充足的计算存储资源.但是受制于网络带宽等因素,云不能及时地处理大量的数据.云方案采用静态密码的验证和明文存储的机制,也存在着安全性问题.区块链技术的兴起,为解决物联网安全问题带来了新思路.边缘计算缩短了数据处理距离,增强了实时性.因此,本文将使用这两项技术,解决目前物联网中的问题.