土体冻结过程中的盐分场研究

As to salty soil, salt migrates with water in freezing soils, assembles and crystallizes continuously. Consequently the swelling of the soil volume leads to the phenomenon of salt heaving. It has a practical significance for solving salt-heaving and frost-heaving damage in engineering to deepen the understanding of salt heaving mechanism. In this paper a general overview about new research results at this aspect was presented. And then the study of salt migration and salt heaving mechanism and present salt heaving models were summarized. For further researching the field of salt transfer it is urgent to continually strengthen the salt migration and the numerical simulation study of salt heaving mechanism to expect perfecting the general evaluation of salt heaving prediction models so as to have a better service for engineering.     

实验研究不同盐离子对水分子拉曼效应的影响

对流体包裹体中常见的几种盐水溶液进行了拉曼光谱分析.采用了频移参数描述水分子拉曼峰的形变强度,并讨论了频移参数与盐度之间的关系.实验分析结果表明,盐度越大,频移参数越大,水分子拉曼峰形变越大.对频移参数曲线斜率分析显示,盐类对水分子拉曼峰偏移程度影响的强弱顺序为NaCl＞Na2SO4＞NaHCO3＞Na2CO3.讨论了不同阳离子和阴离子对水伸缩振动拉曼峰的影响,结果表明,高价阳离子的影响明显高于低价阳离子;而阴离子对水拉曼峰影响的强弱顺序初步确定为Cl-≈SO2-4-＞HCO-3＞CO2-3≈NO-3.     

阿尔金山羌塘高原水资源开发及罗布泊钾盐矿建设的设想

阿尔金山水资源相对丰富,是巴音郭楞蒙古自治州河川径流的主要形成区之一,巴音郭楞蒙古自治州若羌县罗布泊镇钾盐贮量很大,经济效益可观,但水资源成为了罗布泊钾盐矿发展的限制性因素。能否把阿尔金山的水资源作为罗布泊钾盐矿发展的支撑,是我们必须回答的一个问题。本文利用新疆维吾尔自治区水利厅阿尔金山野外考察资料,分析阿尔金山的水系与湖泊、自然地理和社会经济特点,以期为探讨阿尔金山能否作为罗布泊钾盐矿开发的水源条件提供理论依据。     

水盐胁迫对花花柴种子萌发的影响

 水盐胁迫直接影响盐生植物的种子萌发,本研究通过对盐生植物花花柴种子带冠毛与否及不同胁迫处理下种子萌发率的比较分析,探讨花花柴种子萌发期的耐盐特性。对花花柴带冠毛和不带冠毛种子在蒸馏水中的对比萌发结果表明,冠毛对花花柴种子的最终萌发率无影响,但明显延长种子的萌发时间,可能与阻碍种子吸水有关。花花柴种子经过冷处理,成熟的种子没有出现生理休眠现象,有利于种子在条件适宜时迅速起始萌发。采用不同浓度NaCl和等渗的PEG6000 (聚乙二醇) 处理花花柴种子,结果表明：①NaCl和PEG胁迫对花花柴种子的萌发具有非常明显的抑制作用,主要表现为降低种子的萌发率,延长种子的萌发时间,抑制胚根和胚芽的生长;②NaCl对花花柴种子萌发的抑制作用明显地大于等渗的PEG,说明离子胁迫是影响花花柴种子萌发的主要因素;③花花柴种子萌发的耐盐临界值为213 mM,极限值为340 mM;④低浓度的NaCl溶液（50 mM）不影响花花柴种子的萌发和胚芽的生长,表明花花柴种子适宜在低盐条件下萌发;⑤盐胁迫下未萌发种子的复水实验结果表明,高盐处理后未萌发的种子具有较高的复萌率,但各处理下种子最终萌发率没有显著差异,表明高盐能使种子休眠,但种子的活力仍能保持,有利于种群的维持。     

三轴应力状态下盐岩强度分析探讨

通过分析盐岩在三轴应力状态下的变形,说明了较高围压下盐岩的大变形特性,提出了三轴应力状态下,利用轴向荷载除以试件初始横截面面积得到应力-应变关系存在的问题,据此对工程应变和对数应变进行了分析和对比,阐明了这两种应变的适用条件,并开展了不同围压下的试验测试和对试验结果对比分析。研究揭示了应利用对数应变分析盐岩的大变形特性和对变形后的应力进行修正,得到了盐岩的工程应变和对数应变均可表示为围压的线性函数,围压为20 MPa时的轴向压缩变形量是5 MPa时的3.09倍。围压越高,对数应变修正得到的最大轴向应力与不修正的差值越大,用对数应变修正后的轴向应力低于不修正的结果,围压达到20 MPa时,前者仅为后者的63.85%。     

Formation of elongated granite–migmatite domes as isostatic accommodation structures in collisional orogens

The mid-Carboniferous Pelhřimov core complex, Bohemian Massif, is a crustal-scale elongated granite–migmatite dome interpreted to have formed by gravity-driven diapiric upwelling of the metapelitic middle crust. The vertical diapiric flow is evidenced by outward-dipping foliation and lineation patterns, deformation coeval with the widespread presence of melt, rapid exhumation of the dome center from depths corresponding to pressure of about 0.6 GPa to shallow levels (pressure less than 0.2 GPa) within 2 M.y., and kinematic indicators of downward return flow of the mantling rocks. As compared to common diapirs, however, the Pelhřimov complex exhibits a more complicated inferred strain pattern with two perpendicular, irregularly alternating directions of horizontal extension in what is interpreted as the diapir head. Comparison of structural data from migmatites with anisotropy of magnetic susceptibility (AMS) data in granites also reveals that only final increments of strain are recorded in the granites. The map dimensions and gravity image of the complex suggest that the diapiric upwelling affected a large portion of the orogen's interior between two microplates brought together during continental collision. The northwesterly microplate (the upper-crustal Teplá–Barrandian unit) collapsed vertically as an ‘elevator’ at around 346–337 Ma whereas the easterly microplate (Brunia) was underthrust beneath the Moldanubian rocks during ∼346–330 Ma (the indentor). It is suggested that these microplates then acted as cold and rigid margins localizing mid-crustal diapirism and associated voluminous S-type granite plutons inbetween, parallel to the edge of the Brunia indentor.We conclude that bringing together soft metapelitic middle crust with two rigid lithospheric blocks during collision resulted in significant lateral temperature and strength variations across the orogen's interior. A general conclusion from these inferences is that granite–migmatite domes delineating margins of collided microplates may form as crustal-scale structures accommodating late-orogenic isostatic reequilibration.     

Discontinuous behaviour near excavations in a bedded salt formation

Summary Discontinuous behaviour is being observed and measured in the vicinity of excavations constructed in a bedded salt formation 650 m below ground surface for the Waste Isolation Pilot Plant (WIPP) Facility. The 2 m thick salt layer in the immediate roof acts as a beam, shearing along a thin overlying anhydrite/clay seam. Vertical separations between the immediate roof layer and the overlying strata are often observed at the anhydrite/clay seam above the centre of excavations of larger span (11 m). The floor of the excavations is comprised of a 1 m thick salt layer underlain by a 1 m thick predominately anhydrite layer (referred to as MB139). Fractures in MB139 develop beneath most excavations, with increased fracture frequency with drift span and age. In the excavations of larger span (11 m), MB139 eventually debonds along the underlying clay layer. The salt layer overlying MB139 develops both shear and tension failure. In a few locations below excavations of large span, continuous fracture systems are developing from rib to rib through MB139 and the overlying salt. In the ribs, there is limited fracturing within the first metre of most larger excavations. Vertical fractures develop in pillars at most intersections. The discontinuous behaviour is qualitatively consistent with analyses of the formation behaving as a layered medium (elastic beam analysis) and limited tensile and compressive failure of the rock salt. The significance of the discontinuous behaviour is that it can dominate the effective fluid transport properties of the formation near the excavation, and therefore requires consideration in the design of repository seals. Discontinuous behaviour must be monitored and is an important factor in the maintenance programme designed to assure a safe underground environment.     

罗源湾海岸盐沼悬沙粒度及沉降速率的观测和分析

海岸盐沼对环境变化的响应非常敏感,是研究全球变化和人类活动对海岸带环境影响的典型区域之一。影响盐沼演化过程的一个非常重要的因素就是水体悬沙特性[1]。在沿岸水域环境中,有机和无机的细颗粒悬沙在物理和化学的作用下絮凝成大颗粒的絮凝体,其粒径和沉降速率通常是分散细颗粒悬沙的好几倍,因此絮凝过程基本上改变了细颗粒悬沙的水动力行为过程[2]。絮凝体因相对分散颗粒物有较高的沉降速率,水中的悬沙更容易沉降到滩面,控制着水体中的细颗粒物质的沉降通量[3]。     

Anthropogenic impacts on the water and salt budgets of St Lucia estuarine lake in South Africa

Lake St Lucia in South Africa is part of a UNESCO World Heritage site and a Ramsar wetland of international importance. Like many coastal wetlands worldwide, anthropogenic activities including catchment land-use changes, water diversions/abstractions, and manipulation of the mouth state have significantly affected its functioning over the past century. Questions concerning its sustainability have motivated a re-evaluation of management decisions made in the past and of options for the future. A model for the water and salt budgets has therefore been used to investigate “what if” scenarios in terms of past anthropogenic interventions. In particular, simulations allow us to evaluate the effects of diverting the Mfolozi river from St Lucia on the functioning of the system and on the occurrence of various water level/salinity states that drive the biological functioning of the ecosystem. In the past, when the St Lucia estuary and the Mfolozi river had a combined inlet, the mouth was predominantly open. The lake had relatively stable water levels but variable salinities that increased during dry conditions due to evaporative losses and saltwater inflows from the sea. If the mouth closed, the Mfolozi flow was diverted into the lake which reduced salinities and maintained or increased water levels. Simulations indicate that without a link to the Mfolozi the lake system would naturally have a mainly closed inlet with lower average salinities but more variable water levels. During dry conditions water levels would reduce and result in desiccation of large areas of the lake as has recently occurred. We conclude that the artificial separation of the St Lucia and Mfolozi inlets underpins the most significant impacts on the water & salt budget of the lake and that its reversal is key to the sustainability of the system.     

昆明盐矿三维建模及溶通性分析

针对地下盐矿在开采过程中,随时可能会因为溶通状况的改变而发生坍塌地质灾害,本文利用矿山数字管理软件Quanty Mine,确定昆明盐矿的三维模型,以期监控盐矿开采不同阶段溶通的变化规律,为避免盐矿过度开采导致地质灾害的发生。