苏州市区多种地下地质资源协同开发利用研究

地下空间、地下水、浅层地热能和地质材料是重要的地下地质资源,协同开发利用是大势所趋。苏州既是历史文化名城又是现代国际化大都市,城市发展至今对地下地质资源的需求相当迫切。通过对苏州各类地下地质资源的的识别分析,表明其具备分别开发地下空间、地下水、浅层地热能和地质材料资源的能力。若多种资源协同开发,平面上开发利用条件较好,竖向尺度地下浅层到次深层适宜地下空间和地质材料的协同开发,而深层适宜以浅层地热能为主的协同开发。结合苏州国土空间发展格局和地下资源的优势分布特征,城镇空间建议采取“地下空间+浅层地热能”的协同利用模式;农业空间建议采取以“浅层地热能”为主的协同利用模式;生态空间予以生态环境保护。     

Passive Surface-Wave Waveform Inversion for Source-Velocity Joint Imaging

Surveys in Geophysics - Reliable dispersion measurement between two seismic stations is an essential basis of surface wave imaging. Noise source directivity has become an inescapable obstacle and a...     

基于GIS和RS的延安地区土地利用及生态脆弱性评价

基于延安市8个区县1997年、2004年和2011年的TM影像数据,运用遥感和地理信息系统软件,对延安地区自退耕还林(草)政策实施以来土地利用动态变化的数量、速度及其空间格局特征进行了定量分析,并结合经济、社会和自然因素数据,通过主成分分析法对延安地区生态脆弱性进行评价。结果表明,1997年至2011年,延安地区的土地利用类型发生了很大变化。耕地面积呈现减少的趋势;居民用地面积处于增长的态势;林地面积增加,并且后期的增加速度明显大于前期;草地面积有小幅度的减少;未利用地和水体面积呈先减少后增加的趋势。生态脆弱性评估表明,在延安地区的8个区县中,北部四县的生态脆弱性指数比南部四县高。在1997年至2011年期间,研究区域内生态环境脆弱性指数逐渐减小,生态环境安全性逐渐增强。     

水库联合运行对库下汛期河道过水断面形态参数变化率的影响——以黄河内蒙古河段为例

水库联合运行对于库下河道的影响是河流地貌学近年来的热点问题,如何定量表征河道的因应调整则是其难点所在。基于同水位河道过水断面形态参数变化率分析方法,针对黄河内蒙古河段磴口、巴彦高勒、三湖河口、头道拐4个水文站,利用刘家峡水库、龙羊峡水库联合运行之前的1978-1982年、之后的2008-2012年汛期前后实测断面资料,计算了相应年份上述各站同水位下的河道断面面积、水面宽、平均水深等特征参数在经历汛期冲刷后的变化率。结果表明,每年在经历汛期洪水冲刷之后,上述形态参数总体上以增大为主,变化率为正值;大型水库联合运行之前与之后的两个时期相比,同水位下河道断面面积、水面宽和平均水深的变化率分别减小了3.4、3.5和2.8倍。过水断面形态参数的沿程空间变化也由之前的上凸形曲线变为之后增减相间的"S"形曲线。其原因在于,大型水库联合运行削减了洪峰流量、降低了汛期最大流速,从而导致洪水造床能力显著变弱,河道断面形态参数的变化率因之显著减小。大型水库联合运行使黄河内蒙古河道明显萎缩,这不利于可能遭遇的极端大洪水的安全行洪,因此,需要合理利用这些水库的调节功能,有效控制汛期总水沙量和洪峰流量,避免因过度调节而使河道持续萎缩,为可能出现的极端大洪水的安全行洪创造条件。     

1990-2009年珠三角县域城市潜力的时空关联分析(英文)

According to the highway data and some socioeconomic data of 1990, 1994, 2000, 2005 and 2009 of county units in the Pearl River Delta, this paper measured urban integrated power of different counties in different years by factor analysis, and estimated each county’s potential in each year by means of expanded potential model. Based on that, the spatio-temporal association patterns and evolution of county potential were analyzed using spatio-temporal autocorrelation methods, and the validity of spatio-temporal association patterns was verified by comparing with spatial association patterns and cross-correlation function. The main results are shown as follows:(1) The global spatio-temporal association of county potential showed a positive effect during the study period. But this positive effect was not strong, and it had been slowly strengthened during 1994–2005 and decayed during 2005–2009. The local spatio-temporal association characteristics of most counties’ potential kept relatively stable and focused on a positive autocorrelation, however, there were obvious transformations in some counties among four types of local spatio-temporal association(i.e., HH, LL, HL and LH).(2) The distribution difference and its change of local spatio-temporal association types of county potential were obvious. Spatio-temporal HH type units were located in the central zone and Shenzhen-Dongguan region of the eastern zone, but the central spatio-temporal HH area shrunk to the Guangzhou-Foshan core metropolitan region only after 2000; the spatio-temporal LL area in the western zone kept relatively stable with a surface-shaped continuous distribution pattern, new LL type units emerged in the south-central zone since 2005, the eastern LL area expanded during 1994–2000, but then gradually shrunk and scattered at the eastern edge in 2009; the spatio-temporal HL and LH areas varied significantly.(3) The local spatio-temporal association patterns of county potential among the three zones presented significant disparity, and obvious difference between the eastern and central zones tended to decrease, whereas that between the western zone and the central and eastern zones further expanded.(4) Spatio-temporal autocorrelation methods can efficiently mine the spatio-temporal association patterns of county potential, and can better reveal the complicated spatio-temporal interaction between counties than ESDA methods.     

10Be Exposure Ages Obtained From Quaternary Glacial Landforms on the Tibetan Plateau and in the Surrounding Area

In situ terrestrial cosmogenic nuclide (TCN) exposure dating using ¹⁰Be is one of the most successful techniques used to determine the ages of Quaternary deposits and yields data that enable the reconstruction of the Quaternary glacial history of the Tibetan Plateau and the surrounding mountain ranges. Statistical analysis of TCN ¹⁰Be exposure ages, helps to reconstruct the history of glacial fluctuations and past climate changes on the Tibetan Plateau, differences in the timing of glacier advances among different regions. However, different versions of the Cosmic‐Ray‐prOduced NUclide Systematics on Earth (CRONUS‐Earth) online calculator, which calculates and corrects the TCN ages of Quaternary glacial landforms, yield different results. For convenience in establishing contrasts among regions, in this paper, we recalculate 1848 ¹⁰Be exposure ages from the Tibetan Plateau that were published from 1999 to 2017 using version 2.3 of the CRONUS‐Earth calculator. We also compare the results obtained for 1594 ¹⁰Be exposure ages using different versions (2.2, 2.3 and 3.0) of the CRONUS‐Earth calculator. The results are as follows. (1) Approximately 97% of the exposure ages are less than 200 ka. A probability density curve of the exposure ages suggests that greater numbers of oscillations emerge during the Holocene, and the peaks correspond to the Little Ice Age, the 8.2 ka and 9.3 ka cold events; the main peak covers the period between 12 and 18 ka. (2) In most areas, the newer versions of the calculator produce older ¹⁰Be exposure ages. When different versions of the CRONUS‐Earth calculator are used, approximately 29% of the ¹⁰Be exposure ages display maximum differences greater than 10 ka, and the maximum age difference for a single sample is 181.1 ka.     

初始孔压非均布下一维地基砂垫层优化研究

针对吹填土地基水平排水砂垫层铺设深度优化问题,建立了初始孔压非均布下含砂垫层地基的一维固结模型,利用有限Fourier正弦变换法得出了超静孔压和地基整体平均固结度的解答并通过退化验证了解答的正确性。采用二分法分析了砂垫层的最优铺设深度随时间的演化规律,给出了砂垫层最优铺设深度与时间的关系图。研究表明：在固结初期,砂垫层宜放置在土中初始超静孔压较大的位置;在固结后期,砂垫层的最优设置深度为土体厚度的2/3（单面排水）或者1/2（双面排水）的位置。以预压地基平均固结度达到90%所需时间最短为例,当初始孔压倒三角形、正三角形与梯形分布时,单面排水条件下,应分别在0.52、0.72、0.62倍地基土深度处设置砂垫层;双面排水条件下,应分别在0.42、0.58、0.46倍地基土深度处设置砂垫层。最后通过算例分析了当地基土中砂垫层采用最优铺设深度时,与在中间位置铺设砂垫层、不设砂垫层的情况分别进行对比,当时间因子取0.09时,地基土平均固结度分别提高6%和54%。     

不同排水条件下城市固废一维降解固结解析解

目前关于城市固废的降解固结理论研究均沿用太沙基传统排水边界,但是这样不能完全描述垃圾填埋场中复杂的排水边界条件。因此,在已有的简化降解固结模型基础上引入连续排水边界条件,建立了新鲜面为连续排水边界的饱和城市固废一维降解固结模型。在此基础上,借助特征函数解偏微分方程得到了级数形式的解析解答,解的退化检验和收敛性判断初步验证了其合理性。解析解与已有解答的对比分析显示,引入连续排水边界条件后,超静孔压分布有显著的变化;且解析解可解决初始条件和边界条件的矛盾,能反映边界上孔压消散的时间效应。进一步的参数敏感性分析显示,通过调整界面参数可以模拟各种排水条件,获得从完全不排水到完全排水的连续解答。此外,从排水能力差异会改变降解固结发展速度出发,提出了一种保证填埋场稳定的可行策略。