洛河禹门河水库建坝工程地质条件分析

禹门河水库是洛河上的一座反调节水库 ,坝址地质条件较复杂 ,就拱坝与重力坝两种坝型而言各有优缺点。本文通过对坝址区建坝工程地质条件的研究分析 ,提出禹门河坝址具有良好的建坝条件 ,且重力坝方案优于拱坝方案。     

高美古的大气视宁度

报导了2000年和2001年丽江高美古所观测到的大气视宁度,文中统计了14个晚上的观测数据,得到的平均视宁度为0.97″,变化在0.73″～1.42″之间。这些视宁度值是用国际上天文台站测大气视宁度通用的DIMM方法,采用8ms单幅采样曝光取得的。本文还统计了丽江高美古1995年以来每年12月份的大气视宁度,可以看到高美古不同年份大气视宁度的部分变化情况。     

辽宁省建平县水泉遗址动物考古研究——兼论距今4000年前后北方长城沿线地区动物资源的利用策略

作为草原丝绸之路的起点,辽西地区也是中华文明的起源地之一.文章对辽宁省建平县水泉遗址出土的动物骨骼进行了鉴定和分析.结果 表明,在出土的409件可鉴定脊椎动物骨骼中,家猪(Sus domesticus)骨骼可鉴定标本数(NISP)占比为63.75％(最小个体数(MNI)为14件,占比35.90％),显示家猪为水泉遗址夏...     

Lessons learned and need for instrumented liquefaction sites

Instrumented sites provide essential information for understanding and modeling of ground response and ground deformation. For example, significant new lessons were learned from responses at the Wildlife Liquefaction Array (WLA) including: (1) soil softening led to lengthening of period of transmitted ground motions; (2) soil softening also led to attenuation of short-period spectral accelerations (<0.7 s); (3) amplification of long period motions (>0.7 s) occurred due to liquefaction-induced ground oscillation; and (4) ground oscillation led to a continued rise of pore water pressures after strong ground shaking ceased. A new and expanded instrumented site is being developed 70 m downstream from the old WLA site as part of the NSF Network for Earthquake Engineering Simulation (NEES). The new site has more accelerometers, piezometers and ground deformation measurement devices and the data will be streamed to the NEES-grid in near real time.     

狭长区域GPS水准点的最佳布设与拟合方法的应用探讨

针对实例进行多种GPS水准点布设方案探讨,得出点位的最佳布设。结合代表性的拟合方法,如多面函数法、分区拟合法等,通过实验数据计算比较,得出多面函数拟合法在计算量和精度上是狭长区域GPS高程拟合时的最佳选择。     

含氯盐遗址土盐渍风蚀效应试验研究

盐渍风蚀是中国西北干旱区岩土体盐渍劣化加剧风蚀损耗的一种普遍破坏效应,导致遗址体底部盐渍区掏蚀凹进,严重威胁遗址整体稳定。基于室内试验,采用脱盐遗址土掺入不同含量NaCl后制成重塑样,模拟自然干湿循环条件养护并进行声波测试和风洞试验,就遗址土盐渍劣化和风蚀损耗效应做出初步分析。结果表明:含氯盐遗址土试样盐渍劣化和风蚀损耗过程中含盐量是内在因素,干湿循环起着外助力作用。     

Improved HVSR site classification method for free-field strong motion stations validated with Wenchuan aftershock recordings

Local site conditions play an important role in the effective application of strong motion recordings.In the China National Strong Motion Observation Network System(NSMONS),some of the stations do not provide borehole information,and correspondingly,do not assign the site classes yet.In this paper,site classification methodologies for free-field strong motion stations are reviewed and the limitations and uncertainties of the horizontal-to-vertical spectral ratio(HVSR) methods are discussed.Then,a new method for site classification based on the entropy weight theory is proposed.The proposed method avoids the head or tail joggle phenomenon by providing the objective and subjective weights.The method was applied to aftershock recordings from the 2008 Wenchuan earthquake,and 54 free-field NSMONS stations were selected for site classification and the mean HVSRs were calculated.The results show that the improved HVSR method proposed in this paper has a higher success rate and could be adopted in NSMONS.     

应用粒子群算法优化地位指数曲线模型参数研究

以优势高和地位指数的估测误差最小为目标函数,采用粒子群优化算法求解地位指数曲线模型的参数.结合实例与免疫算法比较,结果表明:粒子群优化算法求解的参数使模型的总体误差更小,精度更高,拟合效果更理想,更加科学合理,同时也提高了幼林的估算精度.研究的结果为森林经营中生长模型参数的求解以及相关研究提供了新的应用思路,也拓宽了粒子群优化算法在林业科学中的应用.     

甘肃平凉闪电定位资料误差分析及其优化

利用陈明理等提出的场地误差优化模式,对2001年甘肃省地形起伏较大的平凉地区地闪定位资料进行了优化处理,并选取雷达回波强度大于35 dBz、回波顶高超过7 km的区域作为优化效果验证参考。结果表明,未经场地误差优化的闪电位置远离对应雷达回波数十公里,而优化后对应的闪电位置进入或接近雷达的强回波区,显然更接近于真实情况,优化以后的方位探测器测向角平均偏差可达05°左右。场地误差优化模式能有效地优化闪电定位资料,这对进一步提高雷电临近预警具有积极的意义。