鲁西煤田滑动构造与矿井灾害

本文阐述了鲁西煤田滑动构造发育的基本特征及其与各种矿井灾害之间的关系，对如何改善生产条件、搞好安全生产等方面进行了初步探讨。     

西藏错那-拿日雍错地堑的第四纪正断层作用及其形成机制探讨

青藏高原内部的近东西向伸展变形在藏南地区形成了一系列近南北向裂谷带,对其中最东端的错那-沃卡裂谷带南段错那-拿日雍错地堑调查结果表明,它是第四纪活动明显的半地堑式断陷盆地。控制该盆地发育的主边界断裂带是近南北走向、倾向东侧和长80～110km左右的盆地西缘正断层,是区域内N90°～92°E方向伸展变形的产物。断裂活动速率的多种估算结果表明,该断裂带百万年时间尺度的平均垂直活动速率介于0.2～0.9mm/a之间;MIS 8和MIS 6以来的断裂平均活动速率的合理估计值是0.6±0.2mm/a;但末次冰期盛冰阶以来的断裂平均活动速率明显增加,介于1.0～2.1mm/a之间,合理的估计值为1.3±0.3mm/a,末次冰盛期以来断裂垂直活动速率的增加极可能是该断裂带进入地震丛集期的反映。该地堑近于严格的南北走向及其与当雄-羊八井地堑相似的活动强度,指示了下地壳物质侧向流动所产生的纵向拉张作用最有利于该区近南北向裂谷带的形成。     

青藏高原东缘理塘乱石包高速远程滑坡发育特征与形成机理

青藏高原复杂的地质构造背景,导致该区地震频发,加之该区异常的气候变化,大型乃至巨型地质灾害发育多,危害大。在遥感解译、野外地质调查、物探、槽探和地质测年资料分析的基础上,论述了乱石包滑坡的发育特征,并对其形成机理进行分析探讨。认为乱石包高速远程滑坡具有如下特征:1乱石包滑坡的滑动方向垂直于理塘-德巫断裂的北西段,乱石包滑坡顶部接近于现代雪线;2乱石包滑坡最大滑行距离达3.83km,滑坡后壁与前缘堆积区的高差约820m,滑体方量0.64×108~0.94×108m3,平均滑动速度约53.25m/s;3测年资料表明,乱石包滑坡形成1980±30a BP左右;4组成滑坡体的岩性主要为花岗岩,在长期构造活动和冷冻风化作用下,节理裂隙发育,呈碎裂岩体。分析表明,乱石包滑坡受断裂构造、地形地貌和古气候变化影响较大,形成机理复杂:1理塘-德巫断裂全新世以来活动强烈,具有强震地质背景,由该断裂活动形成的强震可能是乱石包滑坡形成的主要因素之一,在地震作用下,坡顶部地震波放大,垂直加速度大于水平加速度,岩体发生震胀和抛掷,从而形成高速远程滑动;2距今1800~2000a BP左右时,青藏高原地区的温度变化较大,该时期发生的大规模冰川活动可能是乱石包滑坡发生的主要因素之一;3地震、气候变化的组合也是引起乱石包滑坡发生的成因之一,并形成一个完整的地质灾害链:地震→雪崩→岩崩→高速碎屑流。     

In Situ Stress Measurements in the Lhasa Terrane, Tibetan Plateau, China

Tectonic activities are frequent in the Lhasa terrane because of the ongoing collision between the India and Eurasia plates. Knowledge of the stress state is critical to evaluate the crustal stability and the design of underground excavations. Because of the limitations imposed by natural conditions,little research has been performed on the present crustal in situ stress in the Tibetan Plateau,and further study is imperative. In this study,hydraulic fracturing measurements were conducted in Nyching County(LZX) and Lang County(LX),Lhasa terrane to characterize the shallow crustal stress state. The results indicate that the stress state in the LZX borehole is markedly different from that in the LX borehole,in both magnitude and orientation. At the same measurement depths,the magnitudes of horizontal principal stresses in the LX borehole are 1.5–3.0 times larger than those in the LZX borehole. The stress regime in the LX borehole favors reverse faulting characterized by SHShSv,where SH,Sh,and Sv are maximum horizontal,minimum horizontal,and vertical principal stresses,respectively. The SH and Sh values are approximately three and two times greater than Sv. Fracture impression results reveal that SH in the LX borehole are predominantly N–S,while in the LZX borehole the maximum horizontal principal stress is mainly in the NNE-direction. The heterogeneity of the regional stress state might be a result of the population and distribution of local structures and seismic activities. The stress state in the LX borehole has exceeded the critical state of failure equilibrium,and there is an optimally orientated pre-existing fault near the borehole. It can be concluded that the optimally orientated fault is likely to be active when the stress has built up sufficiently to destroy the frictional equilibrium; it is suggested that research focus should be placed on this in future. The stress states in boreholes LZX and LX indicate uniformity of the regional stress field and diversity of the local stress fields resulting from the interactions among regional dynamic forces,tectonic stress field,and geological structures.     

当前国际环境地质工程(环境岩土工程)研究的热点领域及其相关技术

当前环境地质工程(或称环境岩土工程)(EnvironmentalGeotechnology)国际学术讨论会的频繁召开, 反映了世界各国对解决环境问题的迫切愿望, 预示着一个世纪性的环境地质工程研究热潮已经到来。结合我国的国情分析这些会议所研讨的内容, 将有助于提高对当前环境地质工程热点研究领域的认识, 从而在解决国家所面临的环境问题及经济社会可持续发展中发挥应有的作用。本文是作者对当前国际环境地质工程(环境岩土工程)研究热点领域及其相关技术的集成。由于环境问题的广泛性, 对于国内的传统环境工程地质和地质灾害内容不加重复, 但它们同样重要。     

Variations in hydraulic properties of collapsible loess exposed to wetting and shearing

Acta Geotechnica - Loess landslides induced by rainfall or irrigation frequently occur in the Loess Plateaus, China, and the stress paths followed are similar to water infiltration at a constant...     

青藏高原东缘区域地壳稳定性评价

青藏高原东缘新构造运动复杂而强烈,地震与地质灾害多发,区域地壳稳定性评价工作意义重大。基于地质力学和大陆动力学相互补充的区域地壳稳定性评价理论,选择深部地球物理场、区域构造变形、地震活动、区域构造应力场作为内动力因素,地形地貌、降雨量、河流冲蚀组合计算所产生的地质灾害条件作为外动力因素,地层岩性和活动断裂影响带作为介质因素,进行了区域地壳稳定性评价。结果表明,采用地质要素梯度来反映内动力作用和通过地质环境要素综合分析表现外动力作用是提高评价准确性的有效手段;青藏高原东缘可分为8个构造特征差异显著的一级分区,75个综合因素差别较大的二级分区,653个外动力条件有一定差别的三级分区;总体而言,龙门山断裂、鲜水河断裂和安宁河断裂带构成的Y字型构造格架断裂带附近的地壳稳定性最差,西部次之,东部最好,北部区块较完整,南部复杂破碎。     

川西鲜水河断裂带地质灾害发育特征与典型滑坡形成机理

在对川滇地块鲜水河断裂活动习性、地质灾害发育特征、典型地质灾害实例和稳定性等分析的基础上,探讨了鲜水河断裂带地质灾害的发育特征与大型滑坡形成机理。认为鲜水河断裂对该区内地质灾害有明显的控制作用:1断裂带内岩体结构破碎程度高,导致滑坡沿断裂带呈带状分布,约32.5%的地质灾害发育于距断裂带0.5km范围内,19.77%的地质灾害发育于距断裂带0.5~1.0km内,15.22%的地质灾害发育于距断裂带1.0~1.5km内,滑坡的滑动方向多垂直于断裂走向;2八美"土石林"是在断裂活动作用下形成的碎裂岩体,该类岩体力学强度低,稳定性差,滑坡灾害发育密度大;3断裂带内地震滑坡发育,在强震作用下形成的部分滑坡滑动彻底,现今稳定性较好;在地震作用下部分滑坡处于裂而未滑状态,在适当的外力作用下可发生失稳滑动;4断裂带穿越的斜坡或古地震滑坡,在断裂持续活动作用下,稳定性差并多次发生活动;5强降雨在一定程度上加速了断裂带坡体变形和地质灾害的发生频率。     

菌剂添加对不同树种根际土壤微生物及碳酸钙溶蚀的影响

本实验通过对云南省建水地区植被根际土壤中高产碳酸酐酶（CA）的微生物进行分离筛选和溶蚀效应的测定,将溶蚀效果较好的菌株制成菌悬液进行盆栽实验,探究该菌株对不同树种根际土壤微生物代谢活性和碳酸钙类岩石溶蚀效应的影响。结果表明:从根际土壤中筛选到一株能够高产CA,且具有较强溶蚀效果的沙雷氏菌,施加该菌剂的处理组显著增加了土壤微生物数量,提高微生物的代谢活性和多样性,并加速碳酸钙类岩石的溶蚀。本研究旨在为今后岩溶区生态恢复过程中植物树种的选择与微生物菌剂的联合应用提供一种技术手段,为岩溶地区生态系统的治理提供一定的理论支持。      

Molecular phylogeny of familiar flatfish species(Pleuronectidae) in the northwestern Pacific Ocean based on mitochondrial cytochrome oxidase I gene

A molecular phylogenetic analysis was undertaken to evaluate the present systematic status of commercially familiar Pleuronectidae fishes in the northwestern Pacific Ocean. We sequenced a 529 bp fragment of the mitochondrial DNA （mtDNA） COl gene from 34 individuals of these familiar flatfishes from 11 species of nine genera collected in China and Japan. Genetic relationships among haplotypes of specimens from 11 species for COI gene data were reconstructed using the neighbour-joining method and the maximum parsimony （MP） method. The resulting molecular phylogeny of the 11 species, with a few exceptions, supported the existing taxonomy which was based largely on the morphological characteristics. The most noteworthy findings were that the genus Pleuronichthys diverged before deriving of the common ancestor for the other species; the stone flounder, Kareius biocoloratus, should belong to the genus Platichthys with the latin name Platichthys biocoloratus and the genus Verasper was not the extraordinary differ- entiation from the other species in family Pleuronectidae. The resultant phylogenetic trees were also consistent with multiple origins of direct development within family Pleuronectidae. New proof not only for further illuminating the multiple origins of Pleuronectidae but also for confirmation of the evolutionary relationships among groups in the family will be supported.