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991.
沿海吹填砂土地基地下水位较高、常含软土夹层,地基处理难度大。为了研究高能级强夯在这类吹填砂土地基上的加固效果,在山东沿海某吹填砂土场地开展6 000和8 000 kN·m能级强夯加固试验。试验结束后分别运用标准贯入试验、静力触探试验、平板载荷试验进行现场检测。通过对比分析了设计要求深度范围内标准贯入试验和静力触探试验,发现夯前夯后标准贯入试验击数和静力触探锥尖试验阻力均明显提升,有效消除了饱和砂土和饱和粉土的液化势;通过平板载荷试验p-s曲线及夯后静力触探锥尖阻力标准值与承载力特征值的关系式,得到夯后砂土地基承载力特征值≥120 kPa,验证了高能级强夯方案的可行性。其次,对软土夹层位置和地下水位高度展开研究,发现软土层会阻碍夯击能传递,减小强夯有效加固深度,且软土层位置不同对强夯加固效果影响程度不同,强夯影响临界范围处存在软土层时,有效加固深度为软土层顶部位置处;对砂土地基进行4 000 kN·m能级强夯试验时,发现未降水强夯后有效加固深度为5 m,降水至地面以下3 m强夯后有效加固深度达到了7 m,提高了加固效果。在高能级强夯研究基础上,对现场吹填砂土地基进行了75万m2的大面积高能级强夯施工,发现处理后地基能够满足建筑用地要求。 相似文献
992.
海绵城市建设以低影响开发为核心,其核心技术措施中的“渗、蓄、滞、净、用、排”与地质环境密切相关。从地质环境适宜性的角度出发,以常州城市规划区为对象,基于GIS类软件,使用层次分析法、综合评分法等方法,综合考虑研究区的地形地貌、包气带特征、浅层含水层特征及地质灾害情况,构建了常州城市规划区海绵城市建设地质环境评价模型,分析了影响海绵城市建设的主要地质因素,并评价了该区地质环境适宜性。主要结论有:浅层含水层岩性与厚度、包气带岩性及地质灾害易发性是影响常州市海绵城市建设最主要的地质因素;研究区海绵城市地质环境整体较好,适宜性在中等及以上地区分布面积占总面积的89.69%。构建的地质环境评价模型可为同类型海绵城市地质环境评价与城市建设提供技术支撑。 相似文献
993.
Acta Geotechnica - Recently, the buckling failure of piles in liquefiable soils has attracted considerable critical attention. Several studies have documented that a pile may fail by buckling under... 相似文献
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996.
Hai Zhao Wenchao Su Peng Xie Nengping Shen Jiali Cai Ming Luo Jie Li Zhian Bao 《中国地球化学学报》2018,37(3):384-394
The Dachang tin-polymetallic district, Guangxi, China, is one of the largest tin ore fields in the world. Both cassiterite-sulfide and Zn–Cu skarn mineralization are hosted in the Mid-Upper Devonian carbonate-rich sediments adjacent to the underlying Cretaceous Longxianggai granite (91–97 Ma). The Lamo Zn–Cu deposit is a typical skarn deposit in the district and occurs at the contact zone between the Upper Devonian limestone and the granite. The ore minerals mainly consist of sphalerite, arsenopyrite, pyrrhotite, galena, chalcopyrite, and minor molybdenite. However, the age of mineralization and source of the metals are not well constrained. In this study, we use the molybdenite Re–Os dating method and in-situ Pb isotopes of sulfides from the Lamo deposit for the first time in order to directly determine the age of mineralization and the tracing source of metals. Six molybdenite samples yielded a more accurate Re–Os isochron age of 90.0 ± 1.1 Ma (MSWD = 0.72), which is much younger than the reported garnet Sm–Nd isochron age of 95 ± 11 Ma and quartz fluid inclusions Rb–Sr isochron age of 99 ± 6 Ma. This age is also interpreted as the age of Zn–Cu skarn mineralization in the Dachang district. Further, in this study we found that in-situ Pb isotopes of sulfides from the Lamo deposit and feldspars in the district’s biotite granite and granitic porphyry dikes have a narrow range and an overlap of Pb isotopic compositions (206Pb/204Pb = 18.417–18.594, 207Pb/204Pb = 15.641–15.746, and 208Pb/204Pb = 38.791–39.073), suggesting that the metals were mainly sourced from Cretaceous granitic magma. 相似文献
997.
悦康药业在开发和生产过程中可能会对区域地下水环境造成影响。基于研究区水文地质条件,建立水文地质概念模型,分别对拟开采的第Ⅲ承压含水层,运用水流运动方程对项目开采15年后的地下水位进行模拟预测;运用溶质运移数学模型对药厂建成后污水处理站对潜水和第Ⅰ承压水进行污染物模拟预测。水位模拟结果表明,15年后含水层(组)中形成降落漏斗大于1 m的范围为0. 45 km~2,形成地面沉降的可能性较小。污染物模拟预测选取COD_(Mn)、氨氮作为预测因子,分别预测污染发生100天、720天及1 800天后污染物迁移情况。污染物模拟结果表明污水站溶质扩散范围较小,5年后COD_(Mn)最大迁移距离为40 m,中心体积质量降为5. 0 mg/L;氨氮最大迁移距离为35 m,中心体积质量降为0. 3 mg/L,对区域地下水水质影响不大。 相似文献
998.
Jinbao Su Shuwen Dong Yueqiao Zhang Licheng Ma Xuanhua Chen Yong Li 《International Geology Review》2018,60(3):365-381
The mid-Neoproterozoic tectonic setting of the Jiangnan Orogen (JO) is uncertain due to the ongoing debate regarding the history of interactions between the Yangtze and Cathaysia Blocks. Extensive magmatic rocks with ages >830 Ma are observed in the eastern JO and are reported to indicate their formation conditions; however, such magmatic rocks are rare in the western JO. This paper presents data from samples collected from two ultramafic intrusions in northern Guangxi province that yield SHRIMP U–Pb ages of 848 ± 7 and 836 ± 5 Ma. These two intrusions have similar geochemical compositions; are enriched in LILE (Rb, Ba, Th, and Pb) relative to HFSE (Hf, Zr, Nb, Ta, and Y), reflecting an arc-like signature; and are derived from the same source. The intrusions have positive εNd(t) and εHf(t) values, implying a depleted mantle source. Comparing the Neoproterozoic mafic–ultramafic rocks of the JO, differences exist between the rocks that formed at 860–830, 830–800, and 800–740 Ma in terms of their mantle sources and formation conditions. Considering the geochemical composition and ages of formation of the strata and the deep structure of the western JO, we speculate that the western JO was a back-arc foreland basin, which experienced shallow subduction-related and arc-like magmatism during the period between 860 and 830 million years. In contrast to the western JO, the eastern JO may have been a back-arc basin with oceanic crustal basement during that time. The JO formed between 830 and 800 million years in association with subduction-related collisional magmatism due to the amalgamation of the Yangtze and Cathaysia Blocks. Subsequently, magmatism occurred in the JO that resulted from the post-orogenic extension. 相似文献
999.
利用四川盆地磨溪地区12口井岩心、8口井成像测井资料、14口井的测井评价等资料,系统分析磨溪地区龙王庙组储层特征,划分了储层类型,探讨了储层形成主控因素,预测了优质储层展布。结果表明:1)川中磨溪地区龙王庙组储层主要岩石类型为中粗晶砂屑白云岩,储层中小洞发育,见到大量的构造缝和水平缝,整体表现为中低孔、中-高渗特征;2)龙王庙组储层类型可划分为溶蚀孔洞型、溶蚀孔隙型和基质孔隙型3种类型,其中高角度构造缝、水平缝、网状成岩缝和缝合线4种裂缝与3种储集类型形成整体连通的缝洞体系;3)优质储层主要在中细晶砂屑白云岩颗粒滩相中发育,颗粒滩后期经历3期岩溶作用,特别是表生期“顺层”溶蚀使溶蚀孔、洞型储层横向叠置连片,大面积分布,延伸5~20 km,井间连通性好,形成了孔洞发育的优质储层。 相似文献
1000.
Jinge Wang Aijun Su Qingbing Liu Wei Xiang Hsin-Fu Yeh Chengren Xiong Zongxing Zou Cheng Zhong Junqi Liu Shen Cao 《Landslides》2018,15(7):1425-1435
The Huangtupo landslide is one of the largest and most destructive landslides still deforming in the Three Gorges area of China. In recent years, most studies on this landslide have been based on the data obtained from an investigation conducted in 2001. To further elucidate the geological structure and evolution of the landslide, we began building a field test site in the area of the sliding mass with the fastest deformation velocity in 2009. A group of tunnels with a total length of 1.1 km has been excavated, and nine boreholes with depths between 76.8 and 127.1 m have been drilled into the sliding body. Additionally, relative monitoring devices, such as borehole inclinometers and crack meters, have been installed. Based on the findings of the previous investigation and the latest tunneling, drilling, and monitoring data, a spatial distribution model of the sliding surfaces of the Huangtupo No. 1 riverside sliding mass has been established using the discrete smooth interpolation (DSI) method. Significant differences are revealed between the previous proposed sliding surface and the latest monitoring data. We propose that the Huangtupo No. 1 sliding mass has two sliding surfaces. Thus, the sliding mass can be further divided into two secondary sliding bodies, which are named the No. 1-1 (east) and No. 1-2 (west) sliding masses. The No. 1-1 sliding mass slid first, and the material along the western boundary slid later, producing the No. 1-2 sliding body, which has a smaller volume and shallower depth. The areas, volumes, and thicknesses of each sliding body have been calculated using a digital 3D model. 相似文献