高分辨率反射波地震勘探在城市隐伏断裂探测中的应用——以成都天府新区苏码头断裂为例     

刘远志  刘胜  李大虎  夏友钢  李颖  周德帅 《大地测量与地球动力学》2019,39(9):910-915

采用“三小三高二绝招”的工作方法，通过静校正、多域多方法联合噪音衰减和精细的速度分析获得较高分辨率的地震时间剖面，揭示苏码头断裂的展布位置、构造形态及变形样式等。结果表明，区域构造以冲起式为主，在反冲断层与逆冲断层之间形成冲起构造或逆冲三角构造，在地震剖面上有明显的楔状特征。通过地震测线的断层走向以NE为主，倾向以SE为主，部分断层倾向为NW。  相似文献   

A finite element approach for predicting the full resistance profile of a spudcan deeply penetrating in dense sand overlying clay     

《Applied Ocean Research》2019

This paper presents a finite element approach to calculate the full resistance profile of a spudcan deeply penetrating in dense sand overlying clay, in which a potential for an installing spudcan to experience a sudden uncontrolled punch-through failure exists. A modified Mohr-Coulomb model characterized by incorporating a four-phase variation of the mobilized strength and dilation parameters with an equivalent accumulated plastic strain is developed and tested for the overlying dense silica sand. An extended Tresca model is used for the strain softening of the underlying clay. A series of large deformation finite-element (LDFE) analyses are carried out, varying the strength and dilation parameters as well as the spudcan geometries. A fairly good performance of the present approach is verified by validating against groups of centrifuge tests data, allowing the numerical study to be extended parametrically. The four-phase variation of the mobilized strength and dilation parameters involved in the progressive failure of the upper dense sand is parametrically studied and extended to cover the range of sand relative densities that are of practical interest. Additionally, comparisons with the typical existing LDFE analyses using both simple and sophisticated constitutive models are carried out. It shows that the present approach performs fairly well to calculate the full resistance profile of a spudcan deeply penetration in both thin and thick dense sand overlying clay, especially the peak and post-peak resistance, within around 5% of the corresponding centrifuge tests results.  相似文献   

改进的最小曲率迭代法在重力剖面数据插值中的应用     

朱文武  彭军还  高艳龙  李方舟  贾玥 《大地测量与地球动力学》2019,39(8):810-812

基于将约束点也作为待解算结点的思想，对传统最小曲率迭代法进行改进。改进后的方法在待解算结点周围存在约束点时，避免了根据约束点与待解算结点之间的不同关系需要进行分类推导的复杂过程，同时也避免了因使用泰勒展开式进行分解造成的精度损失，提高了解算精度。  相似文献   

Modification and discussion of the Green-Ampt model for an evolving wetting profile   总被引：1，自引：0，他引：1  

Qiyong Zhang  Yuzhen Kong 《水文科学杂志》2020,65(12):2072-2082

ABSTRACT

The Green-Ampt (GA) model has been widely used to evaluate soil water infiltration. While a simple piston profile is commonly used, the wetting profile of a soil changes during infiltration and a quarter-ellipse has been found to better describe its evolution. This study aims to improve the GA model and discuss the model parameters when the quarter-ellipse profile is utilized. The soil column is divided into three zones: saturated, transient and dry. The variable γ is introduced to express the ratio of the saturated zone depth to the wetting front depth. A modified GA model is derived via mathematical methods, but an exact solution is difficult to obtain. Therefore, a simplified (SGA) model is developed via a segmented method. Compared with the measured results, the SGA model is more accurate than the traditional model. Finally, the model parameters are discussed and a value of γ = 0.5 is recommended.  相似文献   

黄土高原沟谷地貌发育演化研究进展与展望     

熊礼阳  汤国安 《地球信息科学学报》2020,22(4):816-826

黄土沟谷是黄土地貌中最有活力、最具变化、最富特色的对象单元,黄土高原千沟万壑的地貌形态以及触目惊心的侵蚀状态也让区域内沟谷地貌的形成、发育及演化问题成为研究中焦点及前沿性科学问题。近年来,诸多学者采用地学测年法、特征表达法、监测模拟法力图实现对黄土沟谷发育演化进程中“过去-现代-未来”的科学认知。这些研究在相当程度上丰富了黄土沟谷发育过程的认知。本文梳理了黄土高原沟谷地貌演化相关研究的现状,并从黄土高原地貌演化、黄土沟谷发育、基于DEM的沟谷信息提取与表达等研究进行了系统的回顾、梳理与分析。此外,本文提出“黄土沟道剖面群组”概念与方法,试图从新的视角审视黄土沟谷地貌发育演化过程。沟道剖面在黄土沟谷发育演化进程中传递物质能量和累积地形动力,并通过径流节点的串联实现剖面群的连接与组合,形成独特的剖面“群组”模式;该沟道剖面群组是集黄土沟谷地貌特征与过程于一体的综合信息集成体,其三维空间结构是对黄土沟谷地貌发育演化的高度抽象与映射,并可望进一步丰富黄土高原数字地形分析理论与方法体系,为黄土高原黄土地貌成因机理与空间分异格局带来创新的认识。  相似文献   

煤层气井产出剖面测试技术及应用     

张雷  樊洪波  侯伟  张伟  郝帅  孙晓光 《吉林大学学报(地球科学版)》2020,50(2):617-626

现有常规油气井产出剖面测试方法在煤层气井中适应性较差，测试范围和测量工艺等存在局限性，施工成功率低。因此，本文对煤层气井产出剖面测试技术进行了整体的系统化设计和研发。通过紧凑的结构设计、高度集成，研发了一套可同时进行温度、压力、磁性定位、热式流量、探针持气率、微波持气、涡轮流量和超声流量等多参数测量的煤层气井测井仪，并研制了一套一次下井可进行多种测试技术测量的煤层气井产出剖面测试技术。同时提高了测试仪器的精度和抗干扰能力，开发了多任务多窗口的便携地面系统操作，并研制新型偏心测试井口应用于煤层气井，实现修井作业时不间断连续测试。该技术在鄂尔多斯盆地石楼北区块3口煤层气井进行了现场试验，取得精确、连续的测试数据。测试结果显示，石楼北区块8^#+9^#煤层为主力产气、产水层。  相似文献   

Evaporation of the Nerve Agent GB From Common Matrices: A Model‐System Study          下载免费PDF全文

Ishay Columbus  Itzhak Marcovitch  Shlomi Elias  Lea Yehezkel  Dana Marder  Victoria Nahum 《洁净——土壤、空气、水》2018,46(4)

  相似文献   

川滇块体东边界主要断裂带现今运动特征分析   总被引：2，自引：1，他引：1       下载免费PDF全文

朱爽  王洪栋 《地震工程学报》2018,40(1):79-85

基于2009年以来的GPS观测数据,利用块体模型和GPS剖面方法分别计算川滇块体东边界主要断裂带的滑动速度,并结合跨断裂带的区域应变时间序列分析断裂带现今的运动特征。结果表明:从速度场变化来看,2013—2015期的速度场在川滇块体东北部有东向增加的微弱变化;从滑动速率结果来看,鲜水河北段的左旋走滑运动有所增强,拉张运动有所增加;小江断裂带的左旋走滑运动普遍有微弱的增强;从去掉线性的区域应变时间序列结果来看,小江断裂带南段主张应变在2014年底出现了趋势性转折,值得进一步关注。  相似文献   

Application of HVSR to estimating thickness of laterite weathering profiles in basalt     

Stephen Nelson  John McBride 《地球表面变化过程与地形》2019,44(7):1365-1376

Lateritic weathering profiles (LWPs) are widespread in the tropics and comprise an important component of the Critical Zone (CZ). The Hawaiian Islands make an excellent natural laboratory for examining the tropical CZ, where the bedrock composition (basalt) is nearly uniform and rainfall varies greatly. This natural laboratory is employed to assess the utility of the HVSR (horizontal/vertical spectral ratio) method to characterize the shear-wave velocity (V_s) structure of LWPs, particularly the depth to the contact between saprolite and basalt bedrock. LWP thicknesses determined from HVSR provide good agreement with multi-channel analysis of surface waves (MASW) profiles, well logs and outcrop. LWP thicknesses may be estimated from the fundamental mode equation or through forward models. Prior knowledge about the subsurface from well, outcrop, and MASW profiles may greatly aid modeling in some cases. For the 3.2 to 1.8 Ma Koolau Volcano on Oahu, the downward rate of advance of the weathering front varies from 0.004 to 0.041 m/ka. For the 0.44 to 0.10 Ma Kohala Volcano (Big Island of Hawaii) rates vary from 0.013 to 0.047 m/ka. Simple H/V spectra develop in areas where the combined effects of time and elevated rainfall produce thick LWPs with a flat base and a general absence of core stones with an ideal layered geometry. Abundant buried core stones violate the assumption of simple layered geometries and scatter acoustic energy, leading to uninterpretable results. This is common where low rainfall and a young basaltic substrate leave abundant core stones as well as an undulating contact between saprolite and bedrock. Velocity inversions (high V_s intervals within low V_s saprolite) may also be present and originate from relatively intact bedrock horizons or mineralogical changes within saprolite. At Kohala, a gibbsite-rich horizon produces such a velocity inversion due to enhanced weathering and subsequent collapse of saprolite in a discrete horizon. © 2019 John Wiley & Sons, Ltd.  相似文献   

建筑物侧面轮廓线约束的高分辨率遥感影像建筑物高度估算方法     

陈辉  张卡  宿东  王蓬勃 《测绘通报》2019,(9):34-37,72

针对现有利用阴影长度法提取建筑物高度时存在的阴影间相互遮挡问题，提出了一种基于建筑物侧面轮廓线进行建筑物高度估算的新方法。首先，利用RPC模型计算建筑物像点位移的方向与卫星成像角度，再将遥感影像进行旋转，使建筑物像点位移沿水平方向；然后，利用Canny算法进行轮廓检测，并构建一定长度的矩形形态学结构元素，对轮廓图像进行形态学开运算，以提取侧面轮廓线，再利用Hough变换与建筑物角点约束，对所提取的轮廓线进一步筛选；最后，根据卫星侧视成像时建筑物高度与像点位移的几何关系进行建筑物的高度估算。利用实际的高分辨率卫星影像对本文方法进行了验证，并与阴影法估算建筑物高度进行了对比。试验结果证明，利用建筑物侧面轮廓线进行建筑物高度估算平均误差可以达到0.7 m，且实际精度优于使用阴影法进行建筑物高度估算。  相似文献