Ⅶ度抗震设防下牧区居住建筑节能技术研究   总被引：1，自引：1，他引：0       下载免费PDF全文

薛芸 《地震工程学报》2018,40(1):60-65

对抗震设防下的牧区居民建筑进行节能设计,在提高能源利用率及降低能源消耗方面具有重要意义。传统的建筑节能技术主要通过降低建筑的热能消耗来提高能源利用,存在节能效果差且单一的问题。对此,在Ⅶ度抗震设防下,采用ANSYS软件,引入Block Lanczos法对牧区居住建筑结构的模态进行分析,计算出建筑地震作用,并通过分析牧区居住建筑围护结构及门窗材质来优化建筑节能技术。实验结果表明,在内蒙古牧区居住建筑采用改进提出的建筑节能技术,可有效降低能源消耗,从而能够有效利用能源,使其具有一定的优势。  相似文献   

基于波形拟合的中国东海地区410 km间断面附近速度结构研究          下载免费PDF全文

李文兰  魏荣强  崔清辉  高雅健  周元泽 《地球物理学报》2018,61(1):150-160

410 km间断面是地幔转换带的顶界面，对其速度结构和起伏形态开展地震学探测有助于认识地球内部物质组成和相关的地球动力学过程.本文选取了由中国数字地震台网记录到的位于琉球俯冲区的一个中源地震P波宽频带波形资料，利用三重震相波形拟合研究了中国东海地区410 km间断面附近的精细速度结构.结果表明：中国东海地区下方410 km间断面整体表现为一尖锐的速度界面且有8~15 km的小幅抬升；该间断面之上存在52~62 km厚的低速层，其P波速度降低0.5%~1.6%；440 km深度以下存在1.0%~3.0%的P波高速异常.结合前人在该地区的层析成像结果，我们推测该高速异常体与西太平洋俯冲板片在中国东海地区地幔转换带内的滞留有关；板片内水相E分解使得转换带内水含量增加，这引发了410 km间断面的抬升；410 km间断面之上的低速层应与含水矿物脱水导致的地幔橄榄岩部分熔融有关.  相似文献   

STUDY FOR ABNORMAL VARIATIONS OF UNDERGROUND FLUID IN LIJIANG AREA,YUNNAN PROVINCE BEFORE LUDIAN M_S6.5 EARTHQUAKE IN 2014     

YANG Zhu-zhuan  DENG Zhi-hui  YANG Yue-wen  DENG Sheng-chang  LI Qing 《地震地质》2018,40(2):480-498

The study is based on the underground fluid observation data in Lijiang area, northwest Yunnan Province. The data include the water level and temperature in Dangxiao well and Jinjia well, and the ion measurements in Ganze spring. Combining with the data of regional hydrogeology, rainfall, well structures, and the geothermal gradient, we analyzed the variations of each measurement item before the Ludian M_S6.5 earthquake on August 3, 2014 and discussed the possible mechanism for the abnormal variations. The water levels of both Dangxiao well and Jinjia well are influenced by local rainfall, but the former shows hysteresis according to rainy seasons and is the long trend influence; while the latter shows synchronization between high water level and rainy season, indicating good connection between well water and shallow aquifer. The recharge water for Dangxiao well is in relatively low temperature, and the temperature sensor is located at the major connecting section between the well water and the aquifer; the water temperature variation is mainly affected by the discharge status and variation of water level. The Jinjia well is always in static level, and the temperature sensor is below the major connecting section between the well water and aquifer, so the water temperature is affected little by water level variations and in smooth fluctuation. The recharge source for Ganze spring can generally increase the contents of calcium and magnesium ions, so does the conductivity. The water level data of Dangxiao well since 2012 are decomposed with wavelet technique. The results, excluding such high-frequency components as the noise and the semidiurnal and daily wave components influenced by earth tide, are further processed with difference method in order to eliminate the trend effect. The results show that the relative change of water level is enhanced and in relatively rapid increase before the Ludian M_S6.5 earthquake; the corresponding water temperature values are high. The tendency of water level in Jinjia well displays descending, while the corresponding water temperature shows ascending. The content of calcium ion, magnesium ion, bicarbonate ion, and conductivity of Ganze spring are descending, while the content of fluoride ion is ascending. The abnormal variations of underground fluid in Lijiang area appeared in turns and were accompanied with minor earthquakes before Ludian M_S6.5 earthquake, which indicates enhancing of regional stress and increasing of fluid activity.  相似文献   

DATABASE OF LANDSLIDES TRIGGERED BY 2015 GORKHA(NEPAL) M_W7.8 EARTHQUAKE     

XU Chong  TIAN Ying-ying  SHEN Ling-ling  MA Si-yuan  XU Xi-wei  ZHOU Ben-gang  HUANG Xue-qiang  MA Jun-xue  CHEN Xi 《地震地质》2018,40(5):1115-1128

In this study, a detailed database of landslides triggered by the 25 April 2015 Gorkha (Nepal)M_W7.8 earthquake is constructed based on visual interpretation of pre- and post-earthquake high-resolution satellite images and field reconnaissance. Results show the earthquake triggered at least 47 200 landslides, which have a NWW direction spatial distribution, similar with the location and strike of the seismogenic fault. The landslides are of a total area about 110km² and an oval distribution area about 35 700km². On the basis of a scale relationship between landslide area (A)and volume (V), V=1.314 7×A^{1.208 5}, the total volume of the coseismic landslides is estimated to be about 9.64×10⁸m³. In the oval landslide distribution area, the landslide number density, area density, and volume density were calculated and the results are 1.32km^-2, 0.31%, and 0.027m, respectively. This study provides a detailed and objective inventory of landslides triggered by the Gorkha earthquake, which provides very important and essential basic data for study of mechanics of coseismic landslides, spatial pattern, distribution law, and hazard assessment. In addition, the landslide database related to an individual earthquake also provides an important earthquake case in a subduction zone for studying landslides related to multiple earthquakes from a global perspective.  相似文献   

The effects of initial soil moisture conditions on swale flow hydrographs          下载免费PDF全文

Hendrik Rujner  Günther Leonhardt  Jiri Marsalek  Anna‐Maria Perttu  Maria Viklander 《水文研究》2018,32(5):644-654

The effects of soil water content (SWC) on the formation of run‐off in grass swales draining into a storm sewer system were studied in two 30‐m test swales with trapezoidal cross sections. Swale 1 was built in a loamy fine‐sand soil, on a slope of 1.5%, and Swale 2 was built in a sandy loam soil, on a slope of 0.7%. In experimental runs, the swales were irrigated with 2 flow rates reproducing run‐off from block rainfalls with intensities approximately corresponding to 2‐month and 3‐year events. Run‐off experiments were conducted for initial SWC (SWC_ini) ranging from 0.18 to 0.43 m³/m³. For low SWC_ini, the run‐off volume was greatly reduced by up to 82%, but at high SWC_ini, the volume reduction was as low as 15%. The relative swale flow volume reductions decreased with increasing SWC_ini and, for the conditions studied, indicated a transition of the dominating swale functions from run‐off dissipation to conveyance. Run‐off flow peaks were reduced proportionally to the flow volume reductions, in the range from 4% to 55%. The swale outflow hydrograph lag times varied from 5 to 15 min, with the high values corresponding to low SWC_ini. Analysis of swale inflow/outflow hydrographs for high SWC_ini allowed estimations of the saturated hydraulic conductivities as 3.27 and 4.84 cm/hr in Swales 1 and 2, respectively. Such estimates differed from averages (N = 9) of double‐ring infiltrometer measurements (9.41 and 1.78 cm/hr). Irregularities in swale bottom slopes created bottom surface depression storage of 0.35 and 0.61 m³ for Swales 1 and 2, respectively, and functioned similarly as check berms contributing to run‐off attenuation. The experimental findings offer implications for drainage swale planning and design: (a) SWC_ini strongly affect swale functioning in run‐off dissipation and conveyance during the early phase of run‐off, which is particularly important for design storms and their antecedent moisture conditions, and (b) concerning the longevity of swale operation, Swale 1 remains fully functional even after almost 60 years of operation, as judged from its attractive appearance, good infiltration rates (3.27 cm/hr), and high flow capacity.  相似文献   

Artificial recharge efficiency assessment by soil water balance and modelling approaches in a multi-layered vadose zone in a dry region     

Mojtaba Pakparvar  Hossein Hashemi  Meisam Rezaei  Wim M. Cornelis  Gholamali Nekooeian  Sayyed Ahang Kowsar 《水文科学杂志》2018,63(8):1183-1202

To assess recharge through floodwater spreading, three wells, approx. 30 m deep, were dug in a 35-year-old basin in southern Iran. Hydraulic parameters of the layers were measured. One well was equipped with pre-calibrated time domain reflectometry (TDR) sensors. The soil moisture was measured continuously before and after events. Rainfall, ponding depth and the duration of the flooding events were also measured. Recharge was assessed by the soil water balance method, and by calibrated (inverse solution) HYDRUS-1D. The results show that the 15 wetting front was interrupted at a layer with fine soil accumulation over a coarse layer at the depth of approx. 4 m. This seemed to occur due to fingering flow. Estimation of recharge by the soil water balance and modelling approaches showed a downward water flux of 55 and 57% of impounded floodwater, respectively.  相似文献   

How deep can forest vegetation cover extend their hydrological reinforcing contribution?          下载免费PDF全文

Elyas Hayati  Ehsan Abdi  Mohsen Mohseni Saravi  John L. Nieber  Baris Majnounian  Giovanni B. Chirico 《水文研究》2018,32(16):2570-2583

An experimental campaign was set up to quantify the contribution of evapotranspiration fluxes on hillslope hydrology and stability for different forest vegetation cover types. Three adjacent hillslopes, respectively, covered by hardwood, softwood, and grass were instrumented with nine access tubes each to monitor soil water dynamics at the three depths of 30, 60, and 100 cm, using a PR2/6 profile probe (Delta‐T Devices Ltd) for about 6 months including wet periods. Soil was drier under softwood and wetter under grass at all the three depths during most of the monitoring period. Matric suction derived via the soil moisture measurements was more responsive to changes in the atmospheric conditions and also recovered faster at the 30 cm depth. Results showed no significant differences between mean matric suction under hardwood (101.6 kPa) with that under either softwood or grass cover. However, a significant difference was found between mean matric suction under softwood (137.5 kPa) and grass (84.3 kPa). Results revealed that, during the wettest period, the hydrological effects from all three vegetation covers were substantial at the 30 cm depth, whereas the contribution from grass cover at 60 cm (2.0 kPa) and 100 cm (1.1 kPa) depths and from hardwood trees at 100 cm depth (1.2 kPa) was negligible. It is surmised that potential instability would have occurred at these larger depths along hillslopes where shallow hillslope failures are most likely to occur in the region. The hydrological effects from softwood trees, 8.1 and 3.9 kPa, were significant as the corresponding factor of safety values showed stable conditions at both depths of 60 and 100 cm, respectively. Therefore, the considerable hydrological reinforcing effects from softwood trees to the 100 cm depth suggest that a hillslope stability analysis would show that hillslopes with softwood trees will be stable even during the wet season.  相似文献   

Stratification response of soil water content during rainfall events under different rainfall patterns   总被引：2，自引：0，他引：2       下载免费PDF全文

Yinglan A  Guoqiang Wang  Wenchao Sun  Baolin Xue  Anthony Kiem 《水文研究》2018,32(20):3128-3139

Many researchers have studied the influence of rainfall patterns on soil water movement processes using rainfall simulation experiments. However, less attention has been paid to the influence under natural condition. In this paper, rainfall, soil water content (SWC), and soil temperature at 10‐, 20‐, 30‐, 40‐, and 50‐cm depths were simultaneously monitored at 1‐min intervals to measure the variation in SWC (SWCv) in response to rainfall under different rainfall patterns. First, we classified rainfall events into four patterns. During the study period, the main pattern was the advanced rainfall pattern (38% of all rainfall events), whereas the delayed, central, and uniform rainfall patterns had similar frequencies of about 20%. During natural rainfall, rainwater rapidly passed through the top soil layers (10–40 cm) and was accumulated in the bottom layer (50 cm). When a high rainfall pulse occurred, the water storage balance was disturbed, resulting in the drainage of initial soil water from the top layers into the deeper layers. Therefore, the critical function of the top layers and the bottom layers was infiltration and storage, respectively. The source of water stored in the bottom layer was not only rainfall but also the initial soil water in the upper soil layers. Changes in soil temperature at each soil depth were comonitored with SWCv to determine the movement characteristics of soil water under different rainfall patterns. Under the delayed rainfall pattern, preferential flows preferred to occur. Under the other rainfall patterns, matrix flow was the main form of soil water movement. Rainfall amount was a better indicator than rainfall intensity for SWCv in the bottom layer under the delayed rainfall pattern. These results provide insights into the responses of SWCv under different rainfall patterns in northern China.  相似文献   

2017年四川九寨沟7.0级地震前地震应变场分析   总被引：2，自引：1，他引：1       下载免费PDF全文

罗国富  刘忠旺  丁凤和  马禾青  杨明芝 《地震工程学报》2018,40(6):1322-1330

以地震应变场作为地震活动的变量，通过自然正交函数展开方法，计算2017年8月8日四川九寨沟7.0级地震前的地震应变场，提取出震前时间因子的异常变化。计算结果发现应变场前4个时间因子在震前1~3年的中短期异常并不显著，只有第2个和第4个时间因子震前有小幅度的异常变化，分析其原因，时间因子可能受到2008年汶川8.0级地震和2013年岷县漳县6.6级地震前大幅度异常的影响。与时间因子对应的空间等值线形成局部应变高值异常危险区，可能是2013年岷县漳县6.6级地震和2017年九寨沟7.0级地震空间异常的中短期特征。再对比九寨沟7.0级地震前后与松潘-平武7.2级双震的空间异常随时间演变，分析异常发展变化模式的差异，最后应用地震资料的累积频次从物理角度解释异常形成的机制。  相似文献   

内蒙古鲁新井田水文地质条件研究          下载免费PDF全文

赵志强  安美艳  高奎锋  王兆亮  王福芝 《山东国土资源》2018,34(6)

矿产资源开发导致了地下水失衡,地下水失衡又给矿产开发造成了极大的安全隐患,近年来,矿产资源开发与地下水环境保护之间的矛盾愈发凸显。通过对内蒙古鲁新井田典型的水文地质条件进行分析研究,分析采矿导致地下水失衡机理,深入剖析矿井开采充水条件及矿山开发对地下水环境的影响,合理提出了促进矿产开发与地下水保护相互协调的对策建议,为实现"采矿保水"协调统一提供了基础地质依据。为类似地区矿产开发过程中遵循自然规律,趋利避害,保障生产安全,保护地下水环境安全,实现资源绿色开发有较好的指导借鉴作用。  相似文献