台湾地区9.21及3.31地震的地下水位异常统计与介入分析

探讨了9．21及3．31两次强震所引起的地下水位异常形态，由许多地下水位震例资料获得的异常形态是复杂多样的，但同一井水位异常形态也有其再现性。将地下水位在两次地震中的异常进行统计，选取有代表性进行介入模式的量化计算，得知阶变与涌冲两种异常形态可取得特定的介入模式，该成果可作为对地下水位异常现象进行识别时参考。     

基于合成孔径雷达技术及DEM的公格尔山冰川动力特征分析

冰川流速是冰川动力状况的重要标志,利用合成孔径雷达技术能快速获得大范围冰川的表面流速.利用日本高级陆地观测卫星(ALOS)相控阵型合成孔径雷达L波段(PALSAR)及欧洲太空局的ENVISAT/ASAR数据的特征匹配方法获得帕米尔高原公格尔山区冰川表面流速,并结合合成孔径雷达干涉相干与不同时期数字高程模型对公格尔山区典型冰川动力进行分析,获得研究区不同时间基线冰川表面相干性、表面流速以及基于不同时相DEM的典型冰川表面高程变化信息.结果表明:30 a来克拉牙依拉克冰川表面高程下降了(15±12.1)m,表碛区域近期运动速度变化不大;其木干冰川平均表面高程几乎无变化,但2007-2011年夏季表面流速明显减缓,靠近末端附近部分区域可能已经演化为非活动区;姜满加尔冰川位于西风带的迎风坡,积累区面积大,冰川流速较快,无表碛覆盖,但表面高程仍下降了(8.8±12.7)m.编号为5Y663D0009的冰川冰舌表碛覆盖区可能已经演化为非活动区,30 a来表面高程下降(8.6±12.0)m.综合分析表明,冰川规模特别是积累区面积的大小及所处位置、地形对冰川演化具有重要影响.     

Long-term electromagnetic core–mantle coupling and the Earth’s rotation acceleration in the Mesozoic Era

Growth lines in the mineralized tissues of living and fossil organisms often exhibit regular patterns that record daily, monthly, or annual cycles. Growth laminations in fossil corals and other marine invertebrates indicate long-term deceleration of the Earth’s rotation, probably largely due to tidal friction, resulting in a decline in the number of days per year over the Earth’s history. Fossils suggest the rate of decline has not been uniform, with the trend between the late Carboniferous and Cretaceous in particular departing from preceding and subsequent periods. However, insufficient data have obscured the nature and cause of the apparent halt in despinning within this time interval. Here we present new fossil geochronometer data that reveal a sustained acceleration in the Earth’s rotation in the early Mesozoic Era, lasting about 90 million years and producing a decrease in the length of day (LOD) at an average rate of about 3 ms/cy. The coincidence of this acceleration with certain geophysical events including the final assembly of Pangaea and a change in the intensity and stability of the geomagnetic field strongly suggests that its cause is rooted in the deep interior of the Earth. A similar explanation has been proposed for observed decadal variations in the Earth’s rotation. Our results suggest large-scale linkage of rotational variation, tectonics, and the geomagnetic field to core–mantle boundary (CMB) dynamics. Furthermore the newly identified acceleration in the Earth’s rotation which began at the end of the Paleozoic, and the geophysical factors that are associated with it, can ultimately bear on the causal mechanisms behind the Permo-Triassic mass extinction.     

农业气象与我国热区名特优水果生产

龙眼、荔枝和果是我国热带、南亚热带（简称热区）名特优水果．这些水果的花芽分化、开花座果对气象条件要求较严格。本文在分析龙眼、荔枝和果的主要气候生态特性的基础上，结合有关省区的气候资料，作出龙眼、荔枝和果生产的布局区划。     

考虑基质吸力的非饱和土邓肯-张统计损伤修正模型

为反映非饱和地基土变形全过程,以某基础工程非饱和土为研究对象,开展固结排水三轴压缩试验。研究发现,非饱和土的偏应力-应变曲线形态近似双曲线,基质吸力对土体力学行为影响十分明显,基质吸力越大,土体偏应力越高。根据非饱和土变形特性及工程特点,选取邓肯-张双曲线模型作为基础模型,引入统计损伤理论,假设非饱和土微元强度服从Weibull概率密度分布,建立邓肯-张统计损伤模型。通过搭建初始切线模量与基质吸力的联系,建立一种新的考虑基质吸力的非饱和土邓肯-张统计损伤模型。给出参数解析方法,得到Weibull分布参数经验表达式,从而修正模型。分析不同基质吸力条件下非饱和土损伤累积规律,采用所建模型和传统邓肯-张模型对比验证非饱和土偏应力-应变试验曲线,证明所建模型的可行性和合理性。研究成果为非饱和土的力学特性研究及辨识模拟提供一定参考。     

考虑降雨渗流影响的露天煤矿黄土开挖边坡分析

黄土开挖边坡在降雨作用下坡面破坏可分为片蚀破坏、沟状侵蚀、坍塌破坏3个阶段。通过野外现场地质调查,建立调查区域露天煤矿某段运煤大道处黄土开挖边坡三维数值分析模型,采用V-G模型设定渗流边界函数,并以此根据室内外实验设定初始负孔隙水压力;在有限差分软件中运用fish语言将野外现场测得的稳定渗透系数与边坡开挖高度关系编入渗流计算命令流中,模拟了不同降雨强度下孔隙水压力、开挖边坡位移、坡面冲刷程度、最大主应力变化情况,提出黄土区开挖边坡在降雨作用下沟状侵蚀在第三级台阶(坡高60m)左右破坏严重,坡高高于此高度应注意沟状侵蚀的剧烈扩展并加以防治;应在开挖边坡顶部以及台阶坡顶、坡肩处加强监测与防护治理工作。     

Acoustic viscoelastic modeling by frequency-domain boundary element method

Earth medium is not completely elastic, with its viscosity resulting in attenuation and dispersion of seismic waves. Most viscoelastic numerical simulations are based on the finite-difference and finite-element methods. Targeted at viscoelastic numerical modeling for multilayered media, the constant-Q acoustic wave equation is transformed into the corresponding wave integral representation with its Green’s function accounting for viscoelastic coefficients. An efficient alternative for full-waveform solution to the integral equation is proposed in this article by extending conventional frequency-domain boundary element methods to viscoelastic media. The viscoelastic boundary element method enjoys a distinct characteristic of the explicit use of boundary continuity conditions of displacement and traction, leading to a semi-analytical solution with sufficient accuracy for simulating the viscoelastic effect across irregular interfaces. Numerical experiments to study the viscoelastic absorption of different Q values demonstrate the accuracy and applicability of the method.     

四川地区云和空中水资源分布与演变

利用1971～2000年台站云降水资料和NCEP再分析资料,分析了四川地区云和空中水资源的分布与演变。研究发现:四川地区平均总云量为7.2成,低云量4.7成,全年阴天日数193.5天,降水日数154.0天,小到中雨日147.1天;全年大气可降水量为181.7kg.m-2。云有明显的季节变化特征,总云量夏季最高,春季次之,冬季最低,低云量夏季最高,秋季次之,冬季最低。大气可降水量夏季最大,秋季次之,冬季最少。云和小到中雨日的空间分布具有明显的地域性,且夏季分布与全年分布显著不同。在高原上,总云和低云、降水日、小到中雨日呈相反的变化趋势,总云在平均状态附近波动略有减少,而低云、降水日、小到中雨日在平均状态附近波动略有增加;在盆地内,云和降水日的演变趋势相同,总云量、低云量、降水日、小到中雨日都在线性减少。30年来四川地区大气可降水量线性变化则略有增多。     

改革采煤方法防治底板突水

通过现场实测和室内研究表明,采煤技术因素对底板突水的影响很大。如何防治底板突水,这里指出了一条改革采煤方法的途径。     

Experimental simulation of water-inrush disaster from the floor of mine and its mechanism investigation

Mine water inrush is very common in China and can cause hysteretic and severe damages to the safety production of coal mines. Essentially, water inrush from coal floor can be attributed to the connection of cracks and the formation of water channel in floor rocks under the interaction of stress field and seepage field. In this paper, the interaction between cracks, stress field, and seepage field in floor rocks was studied by physical simulation; the evolution law of water inrush from floor cracks was obtained under the fluid-solid coupling effect, and the monitoring of rock stress and seepage pressure was realized by virtue of soil pressure and pore-pressure sensors. The results indicated that the permeability of floor rocks had regional and temporal characteristics due to the cyclical variation of in-situ floor stress. The high-permeability zone occurred under the early mining stress area, and gradually extended and connected inside the floor. As a result, more confined water could flood into the connected cracks and thus changed the seepage field in front of working face. This work provides new approaches and knowledge for researching coal floor water inrush and has important significances for the prevention of coal water disasters.