软岩填料的长期沉降变形特性及分析

通过现场试验路堤和室内模型试验研究了几种较有代表性的软岩填石料的长期沉降变形特性,证明了软岩填石料的长期变形性能除了与填石料的岩石特性和压实密度有关外,风化程度、干湿循环是影响填石料的长期变形性能的主要因素。     

峰峰矿区建筑地基承载力经验公式的确定

在系统整理以往岩土工程勘察报告的基础上,利用本区第②层黄土状粉土的物理力学指标及载荷试验成果,通过三元一次方程得出第②层黄土状粉土的承载力的经验公式,该公式的建立对本区工程建设规划具有一定的指导意义。     

地形对安阳天气变化的影响

安阳位于太行山东侧，受太行山影响，西路冷空气影响时不易产生降水，东路冷空气由于受地形抬升影响，常产生降水。由于下沉增温作用，西路冷空气影响时降温不明显；由于太行山的阻挡作用，东路冷空气影响时，降温持续，如有降雪，则会出现连续低温天气。此外，安阳东、西风较少，偏南风最多，偏北风次之。     

驻马店极端气温分析

利用驻马店10个站气象资料,分析了极端温度的时间变化特征、高温天气与6-8月降水量之间的关系和极端晴热高温、极端湿热高温天气形成的天气背景及影响因子,确定了高温出现的前期预报指标。     

地基微波辐射计探测在黄河上游人工增雨中的应用

利用2003、2004年夏秋季在青海省河南县的地基双频段微波辐射计连续观测资料,在实施系统探测实验以进行辐射亮温值(TB(23.87),TB(31.65))与大气汽态总水汽含量(Q)和云中积分液态水含量(L)值反演处理的基础上,分析了黄河上游河曲地区的云水特征,并进行了降水预测及人工增雨作业指标的探讨。结果表明:在黄河上游河曲地区,7—9月纯晴天无云天气条件下,L值基本为0,表明了统计回归反演的显著性。多云条件下Q值和L值分别在3.76~4.75g·cm-2、227.34~859.42g·m-2的范围内。可降水云天气,Q值在5.23~8.65g·cm-2间,L值在421.18~1016.37g·m-2的范围内;积雨云个例分析表明,在降雨开始前近5小时的降雨酝酿期内,Q及L的增加有明显的波动,但在对流云出现并发展时,Q和L总是急剧上升,在降雨前达到一峰值;由河南站和西安站的Q、L值比较差异可以看出,Q、L值受水汽输送、地形等因素的影响,黄河上游河曲地区的人工增雨潜力有显著的优势;所计算出的降水预测阈值,可作为该地区人工增雨作业指标的参考。     

Deformation Mechanism and Stability of a Rocky Slope

A high slope is located on the side of the spillway at a hydropower station in Southwest China, which has some weak inter-layers inclining outwards. Parts of the slope show heavy weathering and unloading. There appeared deformation and tensile crack either on the surface or on the afteredge of the slope during excavation, and under a platform （elev. 488 m）, two levels of slopes collapsed on the downriver side. Based on the investigation in situ and the analysis of the geological structure, the conceptual model of deformation and failure mechanism was erected for this slope. Furthermore, the deformation characteristics were studied with FLAC^3D numerical simulation. Comprehensive analysis shows that the whole deformation of the slope is unloading rebound in certain depth scope and the whole body does not slide along any weak interlayer. In addition, two parts with prominent local deformation in the shallow layer of the slope show the models of ＂creep sfiding-tensile cracking＂ and ＂slidlng-tensile cracking＂, respectively. Based on the above analysis, the corresponding project of support and reinforcement is proposed to make the slope more stable.     

钻孔灌注桩桩底沉渣压浆处理研究与应用

对桩底沉渣产生的原因、沉渣对灌注桩承载能力的影响以及沉渣的处理作了简要分析,讨论了灌注桩桩底压浆工艺的作用机理。重点结合实际工程介绍了该技术,经检测表明,灌注桩桩底压浆技术的使用有效地处理了沉渣,提高了桩的承载能力。     

High Precision Time Domain Forward Modeling for Crosshole Electromagnetic Tomography

To improve the resolution of crosshole electromagnetic tomography, high precision of forward modeling is necessary. A pseudo-spectral time domain (PSTD) forward modeling was used to simulate electromagnetic wave propagation between two boreholes. The PSTD algorithm is based on the finite difference time domain (FDTD) method and uses the fast Fourier transform (FFT) algorithm for spatial derivatives in Maxwell's equations. Besides having the strongpoint of the FDTD method, the calculation precision of the PSTD algorithm is higher than that of the FDTD method under the same calculation condition. The forward modeling using the PSTD method will play an important role in enhancing the resolution of crosshole electromagnetic tomography.     

Establishing the time of initial human occupation of Liang Bua, western Flores, Indonesia

Liang Bua, a limestone cave in western Flores, has an archaeological and faunal sequence known to span the last 95 ka and is the type-site for a small-bodied hominid species, Homo floresiensis. This paper describes the geomorphic history of this significant site, and presents numerical ages for key events as determined by thermoluminescence dating of sediments (using a dual-aliquot regenerative-dose protocol) and uranium-series dating of flowstones. Our age estimates indicate that Liang Bua existed as a subterranean chamber by 400 ka ago. It was subsequently exposed by the incision of the Wae Racang River, which invaded the cave around 190 ka and deposited an upward-fining sequence of water-rolled boulders and cobbles. The latter conglomerate was partially reworked around 130 ka ago and was capped by flowstones at 100 ka. The conglomerate also contains stone artefacts, which implies that the occupation of the surrounding area is at least as old as the time of emplacement of the conglomerate. After 190 ka, a complex sequence of erosion and deposition led to the accumulation of at least 11 m of sediment in the front chamber of the cave, which proved suitable for hominid occupation. Such geochronological and geomorphological information is extremely valuable for interpreting the archaeological record at Liang Bua and its wider significance.     

不同标度震级关系和台基影响问题探讨

利用近年中国数字地震台网观测报告中的中国及邻区地震目录资料,取能够同时计算面波震级MS和近震震级ML的地震,拟合出2种震级之间的关系,发现与过去使用30余年的换算公式存在系统差别。考虑现代化地震数字观测系统有动态范围大、频带宽、台站多、覆盖区域广、测定精度高的特点,由此拟合的关系应当更可靠。考虑不同误差因素统计面波震级MS和近震震级ML的关系表明,2种震级之间换算和不换算的差别并不大,因此建议MS和ML震级之间不换算为宜。分析地震台站的场地响应发现:一些基岩台的放大因子在1附近,场地响应不随频率变化;处于沉积土层的台站,放大因子在低频段大于1,高频段小于1;还有一些台站在某个频段范围大于1,或者小于1。另外,沉积土层台站的单台震级和台网平均震级差也随周期增大,呈现由负到正的增长趋势。看来并不存在固定的台站校正系数,因此不能把台站校正作为提高震级测定精度的方法。