An improved method of sediment grain size trend analysis in the Xiaoqinghe Estuary,southwestern Laizhou Bay,China     

Qiao Su  Changsheng Peng  Liang Yi  Haijun Huang  Yanxia Liu  Xingyong Xu  Guangquan Chen  Hongjun Yu 《Environmental Earth Sciences》2016,75(16):1185

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Characteristics of deuterium excess parameters for geothermal water in Beijing     

Kai Liu  Xiaojuan Qiao  Baoling Li  Ying Sun  Zhiping Li  Conglin Pu 《Environmental Earth Sciences》2016,75(23):1485

This study investigates the characteristics of geothermal water in 10 geothermal fields in Beijing. The relationships between the deuterium excess parameter (d) and temperature, depth, age of geothermal groundwater, groundwater flow field, and Eh were investigated using geothermal groundwater samples. Results showed that (1) the average d value of geothermal water is 5.4, whereas that of the groundwater in normal temperature is 6.04. The differences are induced by the oxygen isotope exchange during the water–rock interaction, which may be more easily completed in geothermal water than in cold groundwater. (2) The d value increases remarkably with the age of the geothermal groundwater. The d value increases from 11.2 to 14.6 when the age of the geothermal water is 12,760 ± 130 a and 38,960 ± 630 a, respectively. Moreover, the isotope heat exchange for composition of the hydrogen and oxygen isotopes in the geothermal groundwater proceeds sufficiently with time. (3) The d value decreases from 5.72 to 3.03 when the depth increases from 125.13 to 3221 m. Generally, in the same area, the d value decreases with depth because the temperature is increasing. (4) The d value of the groundwater gradually reduces from the northern recharge area to the southern discharge area. The average d value is 7.31 in the northern recharge area and 5.68 in the middle Beijing Depression, whereas the d value in the southern area of Fengheying is ?9.20. The larger difference in d values between the recharge and discharge areas is due to the slower velocity of underwater flow, which induces longer time for oxygen exchange. (5) The relationship between the d and Eh is complex. When Eh is <200 mV, the d value of the geothermal water decreases with the decrease in Eh. When Eh is higher than 200 mV, the d value increases slightly with the decrease in Eh. The study of the characteristics of deuterium excess parameters for geothermal water could provide a scientific isotopic evidence for assessment and exploitation measures in geothermal groundwater systems.  相似文献   

大兴安岭中段龙江盆地热河生物群化石组合及生存时限——来自生物地层、年代地层新证据     

张渝金  杨雅军  蔡闹  吴新伟  张超  郭威 《地质学报》2018,92(2):197-214

龙江盆地光华组层型剖面出露完整,沉积连续,含丰富的热河生物群化石,是大兴安岭中段研究热河生物群起源、演化及辐射的重点剖面之一。本文对光华组层型剖面进行了重新精细测制,认为光华组整合于龙江组安山质角砾熔结凝灰岩之上,被甘河组玄武岩局部不整合覆盖,自下而上可识别出下、中、上3个岩性段;对该组所产动植物化石进行了系统的采集和鉴定,丰富了大兴安岭中段热河生物群的生物类别,并依据新采集化石和前人资料,尝试建立了叶肢介、介形虫、植物化石、昆虫等组合,探讨了各生物组合特征。根据对光华组剖面中段顶底岩层进行了LA-ICP-MS U-Pb锆石年代学研究,揭示龙江盆地热河生物生存的时代为125.4±1.4Ma至120.1±1.1Ma,大致跨越500万年,反映龙江盆地热河生物群繁盛于从阿普特期早期至阿普特期中期。结合古生物特点和笔者前期研究成果,认为龙江盆地热河生物群生存的古环境可能是间歇性或季节性的湖泊;古气候应处于温暖湿润的季节性变化的暖温带,并伴有短暂的半干旱气候。  相似文献   

乌尉高速公路边坡稳定性综合评价          下载免费PDF全文

李元松  高晖  陈峰  王亚军  闫海涛  王章琼  肖尊群 《水文地质工程地质》2018,(4):143-150

针对乌尉(乌鲁木齐至尉犁)高速公路地处高寒、高海拔、高地震烈度区,地质环境条件复杂的特点,提出一种基于多判据的边坡稳定性模糊综合评价方法。首先,分析研究三高地区公路沿线工程地质条件、边坡岩体结构特征及其变形破坏模式。在此基础上,以TSMR评价体系为框架,考虑地震荷载对边坡稳定性的影响,引入地震作用影响系数β,建立了适用于“三高”地区公路边坡岩体质量分级体系THRSMR;基于边坡可靠性分析理论,归纳总结Monte Carlo法的操作步骤,并借助GEO-SLOPE软件,给出各研究边坡的可靠度指标与失效概率;最后,将定性评价、极限平衡分析、可靠度分析和数值计算的结果分别作为基础指标,采用模糊综合评价方法对每一边坡的边坡稳定性,给出进一步量化结论。其结果对类似地区高速公路边坡稳定性评价具有一定的参考价值。  相似文献   

Study on the deformation and failure modes of filling slope in loess filling engineering: a case study at a loess mountain airport   总被引：1，自引：0，他引：1  

Jiading Wang  Yuanjun Xu  Yan Ma  Shaonan Qiao  Kaiqiang Feng 《Landslides》2018,15(12):2423-2435

Lvliang airport is a typical loess filling engineering located in 20.5 km north of Lvliang City in Shanxi Province, China. By the end of March 2012, 14 fissures extending more than 7.5 m were observed in a loess-filled slope, of which the longest fissure is up to 82 m. Field monitoring and laboratory tests have been performed to investigate the slope failure modes. The test program includes wetting tests on unsaturated compacted samples and stress path tests on saturated samples. Field monitoring and observations show that differential settlement caused by non-homogeneity in compacted loess density might lead to the formation of fissures in the loess-filled slope. It was founded that the wetting deformation contributed to the development of differential settlement. Fissures are the essential factor for the loess-filled slope failure. Four deformation stages exhibit in the loess-filled slope prior final failure including development of the fissures, softening of the compacted loess, creeping of the slope leading edge and fissuring of the trailing edge and formation of the through-sliding surface. Development of the sliding surface mainly includes upward and downward expansion of the fissures. Upward expansion is a wetting failure process in loading condition, while downward expansion is a load-off wetting process. In addition, development of the sliding surface is accelerated by softening of the compacted soils as a result of water infiltration. Therefore, the key for taking countermeasures against filling landslides is to monitor and control the development of differential settlement and fissures in the slope shoulders. Digging out and extra-filling the fissures are an effective way for preventing these landslides.  相似文献   

闽赣交界武夷山南段“桃溪穹隆”形变特征及构造演化探讨          下载免费PDF全文

黄昌旗  张开毕  石建基  张达  林子华  程乔  赵举兴 《华东地质》2018,(4):252-260

"桃溪穹隆"由内核、中间层和盖层组成,发育岩石流变,韧性、韧脆性和脆性变形(断裂)。文章以"桃溪穹隆"内核、中间层和盖层为对象,通过研究其形变特征、运动形式及相互关系,探讨穹隆上隆的运动方式,结合沉积事件、岩浆活动和构造运动,阐述穹隆的形成机制和构造演化特征。"桃溪穹隆"于加里东期(志留纪末)隆升,华力西期—印支期(晚二叠世—中三叠世)大规模上隆,燕山期及后期继承性活动,主隆升期(华力西期—印支期)为逆时针旋转上隆。穹隆长期隆升是该区古元古代结晶基底出露的主要原因。  相似文献   

Evaluating climate change adaptation efforts on the US 50 states’ hazard mitigation plans     

Qiao Hu  Zhenghong Tang  Lei Zhang  Yuanyuan Xu  Xiaolin Wu  Ligang Zhang 《Natural Hazards》2018,92(2):783-804

Climate change brings uncertain risks of climate-related natural hazards. The US Federal Emergency Management Agency (FEMA in Climate change: long-term trends and their implications for emergency management, 2011. https://www.fema.gov/pdf/about/programs/oppa/climate_change_paper.pdf) has issued a policy directive to integrate climate change adaptation actions into hazard mitigation programs, policies, and plans. However, to date there has been no comprehensive empirical study to examine the extent to which climate change issues are integrated into state hazard mitigation plans (SHMPs). This study develops 18 indicators to examine the extent of climate change considerations in the 50 SHMPs. The results demonstrate that these SHMPs treat climate change issues in an uneven fashion, with large variations present among the 50 states. The overall plan quality for climate change considerations was sustained at an intermediate level with regard to climate change-related awareness, analysis, and actions. The findings confirm that climate change concepts and historic extreme events have been well recognized by the majority of SHMPs. Even though they are not specific to climate change, mitigation and adaptation strategies that can help reduce climate change risks have been adopted in these plans. However, the plans still lack a detailed assessment of climate change and more incentives for collaboration strategies beyond working with emergency management agencies.  相似文献   

Dynamic Response to Seismic Waves at the Shallow Slope Supported by Bolts     

Jun Wang  Jie Liu  Qiao Liang  Xiangsen Ouyang 《Geotechnical and Geological Engineering》2018,36(4):1991-2001

In the soil slope supported by bolts, longitude waves instead of transverse waves, generated by earthquakes, first reach the slope surface. With the dynamic response of the P (pressure) wave along the anchorage structure, first, a theoretical study was conducted to investigate the propagation characteristics of the interference superposition, generated by the SV (shear-vertical) and the P waves. The SV wave was formed by the wave, originating from the bottom and reflected from the free surface of the slope, whereas the latter was the incident P wave, propagating in the slope. In addition, the structural measures, restraining the seismic wave, and the characteristics of the restraint effect at the free segment of the bolt were investigated. According to the wave-way difference between the incident P wave and the reflected SV wave, the minimum critical slope angle, influenced by the interference at the shallow slope, and the maximum influencing depth of the dynamic response, acting vertically to the slope surface, were obtained. The results indicate that the maximum influencing depth linearly correlated with the slope angle. Furthermore, based on the propagation characteristics of the P wave along the bolt, and the coupled relation between the wave length and the anchorage design parameters, the axial acceleration of the wave propagating along the bolt axis was obtained. Then, the theoretical length of the anti-seismic bolt, subjected to seismic waves, and the compensation force of the anchorage structure were obtained. Finally, a numerical study, based on FlAC3D, properly verified the theoretical conclusions.  相似文献   

断裂应力特征及其转折控油气规律研究——以南堡凹陷为例     

马强  德勒恰提&#;加娜塔依  陈亚军  马乐  于景维  祁利祺 《地质力学学报》2018,24(5):587-597

为了分析断裂对油气宏观分布规律的控制作用,寻找有勘探潜力的油气富集带,文中以地质力学理论为指导,对南堡凹陷断裂组合应力特征、断裂转折及成因进行解析,并结合砂体分布和古今构造应力场分布特征,对南堡凹陷东营组油气分布规律和有利勘探区带做了研究。结果表明:断裂转折部位对油气分布有着控制作用,东营组已探明的油气主要在帚状断裂系、入字形断裂系、交织式断裂系转折轴部高曲率附近呈环带状分布;断裂转折凹面一侧控油性明显,从宏观上来看,油气具有沿沉积相带由细到粗的构造脊高点以及弧形断裂转折凹面一侧的选择性运移的特征,断裂转折轴部高曲率高孔、高渗域与高孔、高渗砂体沉积相带的有利对置决定了油气的主流向;综合研究指出,南堡凹陷北堡构造带是今后优势勘探的首要区带,其次是南堡构造带和南堡4号蛤坨构造带南部。  相似文献   

A noise suppression method for superconducting full tensor aeromagnetic gradient measurement data     

ZiQi Guo  ShuangXi Ji  Yanchao Qiao  Ji Wang 《《地质学报》英文版》2018,92(Z1):367-368

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