Case Histories of Four Extremely Intense Rockbursts in Deep Tunnels   总被引：2，自引：1，他引：1  

Chuanqing Zhang  Xia-Ting Feng  Hui Zhou  Shili Qiu  Wenping Wu 《Rock Mechanics and Rock Engineering》2012,45(3):275-288

In the process of excavating seven parallel tunnels at the Jinping II Hydropower Station, several extremely intense rockbursts occurred, killing and injuring construction workers and damaging several sets of equipment. Based on the characteristics and mechanisms of these rockbursts, four typical events were selected and their temporal and spatial characteristics were here described in detail. The geological conditions revealed after the rockbursts were surveyed carefully. The responses of support elements were also analyzed. The details documented in each case provide not only an important reference for understanding the development mechanisms of rockbursts but also a basis for the selection and development of rockburst prevention measures in deep hard rock tunnels.  相似文献   

Features of the Excess Adsorption Isotherms of High-Pressure Methane Adsorption on Coal and Simulation Model     

CUI Yongjun  ZHANG Dengfeng  ZHANG Qun  LIN Weigang  SONG Wenli  LI Yuhui  JIANG Wenping 《《地质学报》英文版》2010,84(6):1547-1554

<正>Four coal samples of different ranks are selected to perform the adsorption measurement of high-pressure methane(CH4).The highest equilibrium pressure of the measurement exceeds 20 MPa. Combined with the measuring results and theoretical analyses,the reasons for the peak or the maximum adsorption capacity appearing in the excess adsorption isotherms are explained.The rules of the peak occurrence are summarized.And then,based on the features of coal pore structure,the adsorption features of high-pressure gas,the microcosmic interaction relationship of coal surface and CH4 molecule,and the coalbed methane reservoir conditions,three theoretical assumptions on the coal adsorption high-pressure CH_4 are suggested.Thereafter,on the basis of these theoretical assumptions,the Ono-Kondo lattice model is processed for simplification and deformation. Subsequently,the equations modeling the excess adsorption isotherm of high-pressure CH_4 adsorption on coal are obtained.Through the verification on the measurement data,the fitting results indicate that it is feasible to use the Ono-Kondo lattice mode to model the excess adsorption isotherm of high-pressure CH_4 adsorption on coal.  相似文献   

The Tarim picrite–basalt–rhyolite suite, a Permian flood basalt from northwest China with contrasting rhyolites produced by fractional crystallization and anatexis     

Wei Tian  Ian H. Campbell  Charlotte M. Allen  Ping Guan  Wenqing Pan  Mimi Chen  Hongjiao Yu  Wenping Zhu 《Contributions to Mineralogy and Petrology》2010,160(3):407-425

We report major and trace element composition, Sr–Nd isotopic and seismological data for a picrite–basalt–rhyolite suite from the northern Tarim uplift (NTU), northwest China. The samples were recovered from 13 boreholes at depths between 5,166 and 6,333 m. The picritic samples have high MgO (14.5–16.8 wt%, volatiles included) enriched in incompatible element and have high ⁸⁷Sr/⁸⁶Sr and low ¹⁴³Nd/¹⁴⁴Nd isotopic ratios (εNd (t) = −5.3; Sr_i = 0.707), resembling the Karoo high-Ti picrites. All the basaltic samples are enriched in TiO₂ (2.1–3.2 wt%, volatiles free), have high FeOt abundances (11.27–15.75 wt%, volatiles free), are enriched in incompatible elements and have high Sr and low Nd isotopic ratios (Sr_i = 0.7049–0.7065; εNd (t) = −4.1 to −0.4). High Nb/La ratios (0.91–1.34) of basalts attest that they are mantle-derived magma with negligible crustal contamination. The rhyolite samples can be subdivided into two coeval groups with overlapping U–Pb zircon ages between 291 ± 4 and 272 ± 2 Ma. Group 1 rhyolites are enriched in Nb and Ta, have similar Nb/La, Nb/U, and Sr–Nd isotopic compositions to the associated basalts, implying that they are formed by fractional crystallization of the basalts. Group 2 rhyolites are depleted in Nb and Ta, have low Nb/La ratios, and have very high Sr and low Nd isotopic ratios, implying that crustal materials have been extensively, if not exclusively, involved in their source. The picrite–basalt–rhyolite suite from the NTU, together with Permian volcanic rocks from elsewhere Tarim basin, constitute a Large Igneous Province (LIP) that is characterized by large areal extent, rapid eruption, OIB-type chemical composition, and eruption of high temperature picritic magma. The Early Permian magmatism, which covered an area >300,000 km², is therefore named the Tarim Flood Basalt.  相似文献   

������嶫�����˶��ֽ����ȷ��   总被引：2，自引：2，他引：0  

崔笃信  王庆良  王文萍  胡亚轩 《大地测量与地球动力学》2007,27(1):24-30

????о???1999??2004?????GPS??????????????????嶫???????????????????????????????????????????壬??????????????????????2001??11??14 ??????Ms8.1????????????????????????????????????????????????????????λ????????????????????????;????λ??????????????в??????????????????????????λ????????????????????????????γ????????????????????????  相似文献   

����������ڵؿ��˶���Ӧ�����   总被引：8，自引：8，他引：0  

张希  张四新  王双绪  张晓亮  陆明勇  王文萍 《大地测量与地球动力学》2007,27(4):8-15

????1994??2006???????GPS????????????????????????????縺λ???????????????????α????????????о???????????????弰??????????????????????????????????:??????????????????????????????????????;?????????????????????????????????????????-??????鼰??????????????????????????????????????-????????????????  相似文献   

Simulation of a groundwater fall caused by geological discontinuities     

Wenping Li  Zhenying Liu  Haipeng Guo  Ning Li  Weidong Kang 《Hydrogeology Journal》2011,19(6):1121-1133

In some areas close to a reverse fault with significant vertical displacement, or the boundary of a mining area in multi-layer rock and the boundary of perched water, the phreatic water-level changes abruptly from one side of the fault or boundary to the other. There is no direct hydraulic connection between the two sides and a groundwater fall occurs across the fault or boundary. This groundwater fall cannot be easily handled by the modules available in MODFLOW. Semi-analytical solutions were derived for water discharge from the upstream to the downstream side of the fault or boundary, and verified by air-water two-phase numerical simulation. The numerical results show that the derived semi-analytical solutions can be used to accurately estimate the groundwater flux at the fault even though the unsaturated zone is not considered. A module package, GWF, was developed to simulate the groundwater fall, which can be embedded directly into MODFLOW. A theoretical example is presented to show how the package GWF is used to simulate perched water. This package was also applied successfully to build a regional groundwater model of the Urumqi River Basin, Xinjiang, China, and the simulation results showed good agreement with the local hydrogeologic conditions.  相似文献   

中国东部南北样带森林生态系统WUE和NUE空间格局及驱动因子(英文)   总被引：4，自引：1，他引：3  

盛文萍  任书杰  于贵瑞  方华军  姜春明  张弥 《地理学报(英文版)》2011,21(4):651-665

From July 2008 to August 2008, 72 leaf samples from 22 species and 81 soil samples in the nine natural forest ecosystems were collected, from north to south along the North-South Transect of Eastern China (NSTEC). Based on these samples, we studied the geographical distribution patterns of vegetable water use efficiency (WUE) and nitrogen use efficiency (NUE), and analyzed their relationship with environmental factors. The vegetable WUE and NUE were calculated through the measurement of foliar δ 13C and C/N of predominant species, respectively. The results showed: (1) vegetable WUE, ranging from 2.13 to 28.67 mg C g-1 H2O, increased linearly from south to north in the representative forest ecosystems along the NSTEC, while vegetable NUE showed an opposite trend, increasing from north to south, ranging from 12.92 to 29.60 g C g-1 N. (2) Vegetable WUE and NUE were dominantly driven by climate and significantly affected by soil nutrient factors. Based on multiple stepwise regression analysis, mean annual temperature, soil phosphorus concentration, and soil nitrogen concentration were responding for 75.5% of the variations of WUE (p<0.001). While, mean annual precipitation and soil phosphorus concentration could explain 65.7% of the change in vegetable NUE (p<0.001). Moreover, vegetable WUE and NUE would also be seriously influenced by atmospheric nitrogen deposition in nitrogen saturated ecosystems. (3) There was a significant trade-off relationship between vegetable WUE and NUE in the typical forest ecosystems along the NSTEC (p<0.001), indicating a balanced strategy for vegetation in resource utilization in natural forest ecosystems along the NSTEC. This study suggests that global change would impact the resource use efficiency of forest ecosystems. However, vegetation could adapt to those changes by increasing the use efficiency of shortage resource while decreasing the relatively ample one. But extreme impacts, such as heavy nitrogen deposition, would break this trade-off mechanism and give a dramatic disturbance to the ecosystem biogeochemical cycle.  相似文献   

一种融合文本中地理位置和土地利用/覆被信息的野生动物活动细粒度定位方法     

尹文萍  高宸  樊辉  谢菲  张鑫 《地球信息科学学报》2022,24(7):1363-1374

文本蕴含大量地理位置描述信息,有效融合地理关联信息以实现文本的精细定位是地理信息服务的难点。本文提出一种融合土地利用/覆被信息的描述地理位置的细粒度定位方法：在文本描述地理关联信息（地理位置实体、土地利用/覆被实体与空间关系）抽取、土地利用/覆被精细分类与地理位置粗粒度匹配定位的基础上,使用自然语言空间关系近似转换模型,确定地理位置的细粒度定位范围;基于土地利用/覆被实体及其周边精细分类信息,在该范围内检索匹配,确定地理位置的细粒度定位坐标。本文以野生亚洲象活动/肇事监测文本为例开展实验,并用匹配率与位置精度评价定位质量,结果表明：本文方法显著提升了地理位置的细粒度定位质量,实验精确匹配率（81.51%）、位置误差距离的均值（65.97 m）及其≤50 m的比例（70.50%）均优于国内主流在线地理编码与地名检索服务结合空间关系或其单独使用结果。该方法有助于完善地理位置定位方法体系、提升地理信息空间化质量,并可服务于野生动物活动/肇事监测预警等精细定位任务。  相似文献   

Phenotypic correlations of somatic and gonad traits of sea urchins Glyptocidaris crenularis in two sampled periods: first insight into its breeding and aquaculture     

罗世滨  田晓飞  赵冲  周海森  张伟杰  封文萍  常亚青 《中国海洋湖沼学报》2014,32(2):344-348

Prior knowledge of the correlations among commercially important traits in Glyptocidaris crenularis can be used to guide development of breeding and aquaculture programs for this species. We evaluated the phenotypic correlations between somatic and gonadal traits in G. crenularis during two sample periods （October 2010 and April 2011）. The coefficients of variation （CV%） for body weight （BW）, redness （a＊）, yellowness （b＊）, gonad wet weight （GW）, and gonad index （GI） were 〉20% in both periods, while those of other traits were very low. GW was significantly correlated with somatic traits （diameter, height, and body weight） in both periods, although the correlation coefficients ranged from 0.473 to 0.636 （P〈0.01）. Gonad moisture content （GC）, a＊, and lightness （L＊） were not significantly correlated with somatic traits （P〉0.05）. The color trait b＊ was negatively correlated with somatic traits （test diameter, test height, and body weight） during the period when the gonads were well developed （April 2011, P〈0.05）. We observed little difference in the nature of the phenotypic correlations between the two sample periods. The high variation in the somatic and gonad weight traits in G. crenularis suggests there is considerable potential for selective breeding. However, our results suggest that gonad quality traits cannot be selected indirectly by selecting for body weight. Our study provides an insight into the method for improving the breeding and aquaculture of G. crenulari.  相似文献   

改进利用蚁群规则挖掘算法进行遥感影像分类   总被引：1，自引：0，他引：1  

吴孔江  曾永年  靳文凭  何丽丽  李静 《测绘学报》2013,42(1):59-66

基于ant-miner算法,提出改进蚁群规则挖掘算法.首先,从信息素浓度增加项、信息素挥发系数两方面,改进信息素浓度更新策略;其次,在算法求解中,引入变异算子,有效加快进化过程,缩短计算时间,获得较好的分类规则.以长沙市城区2006年TM影像为试验数据,在分类试验中对算法进行了验证.结果表明,相对于ant-miner和决策树方法而言,改进蚁群规则挖掘算法能挖掘出规则数目更少、形式更简单的分类规则,同时缩短计算时间,从而能够提高分类精度和效率.  相似文献