矿山疏干排水引起岩溶地区致塌机理分析与预测——以平顶山矿区七矿及附近区域为例

在分析平顶山矿区水文地质背景和岩溶发育状况以及各岩溶含水层的水力联系基础上,引入岩溶致塌机理确立了岩溶塌陷的判定准则,得出了岩溶塌陷地区的疏干警戒水位公式,从定量上论证煤矿开采疏干排水是该区岩溶致塌的关键因素,当水位下降幅度达到2．52～8．03m时,平顶山七矿及附近区域容易产生岩溶塌陷,同时指出岩溶稳定系数K=1时,是临界危险警戒的地下水降深。     

鹊山龙湖生态驳岸方案探讨

水体是鹊山龙湖景观主体,驳岸是水体周边景观的基础和有机组成部分,如何做到驳岸与景观设计充分融合,体现人与自然、岸与水的和谐性、亲水性及生态性,是驳岸设计的关键。该文对驳岸的一般形式进行了概述,介绍了生态驳岸的概念、分类及常用做法,根据湖区各部位具体情况、景观要求,运用生态驳岸不同类型的特点有针对性地对各不同区域驳岸进行了设计方案的探讨。     

Analysis of riverbank instability due to toe scour and lateral erosion

This paper provides instruction in the use of the computer spreadsheet to undertake the calculations necessary to apply the Osman–Thorne bank stability analysis for steep, eroding riverbanks. The guide explains how to input the necessary parameters into the LOTUS 123 spreadsheet in order to:

• 1 find the initial factor of safety of the bank with respect to slab-type failure;
• 2 test the sensitivity of bank stability to changes in the engineering properties of the bank material;
• 3 analyse the response of bank stability to toe scour and/or lateral erosion and find the critical condition;
• 4 find the geometry of the failure surface and failure block;
• 5 analyse the response of bank stability to further toe scour and/or lateral erosion;
• 6 find the geometry of the failure surface and failure block in subsequent failures.

     

贵州主要城市的岩溶塌陷灾害及其防治

贵州是我国岩溶地貌最发育的省份之一,全省主要城市贵阳、遵义、安顺和六盘水等四个城市都分布在岩溶区。随着城市发展加快,城市岩溶塌陷灾害也日趋突出。本文以贵州四个主要城市为例,阐述岩溶塌陷灾害的概况及危害,分析了岩溶塌陷的发育分布特征,探讨了岩溶塌陷的成因机理,并据此提出了相应的防治对策。     

关于80年代闽南─台湾浅滩渔场中上层渔获量变动原因的初探

近来，1986年中上层渔获量达7．4333万t，1987年史创历史记录高达12．07万t，并且1983年（厄年）金色小沙丁鱼产量也达到1．9587万t，仅次于历史最高水平的1971年的产量，但到1988半的产量仅为2778t，占中上层渔获量3．21％，从而从历史上第一位下降到第4位[1]，如此渔获量变动，其原因何在呢？笔者试就从海洋环境变异，捕捞力度等诸因素合理解释中上层渔获量变功，为科学管理和合理开发中上层鱼类资源寻找理论依据。     

Faroe Bank Channel overflow 1995–2005

The Faroe Bank Channel (FBC) is the deepest passage across the Greenland–Scotland Ridge and there is continuous overflow of dense water through the channel, which provides a substantial contribution to the global thermohaline circulation. Since November 1995, Acoustic Doppler Current Profilers (ADCPs) have been moored at the sill of the channel continuously, except for short annual servicing periods. In addition to this, CTD sections have regularly been occupied across the channel and instruments, recording temperature and salinity, have been moored for short periods. These observations demonstrate that the channel, due to its small width, can be monitored fairly well with only one ADCP mooring and they allow the generation of a time-series of overflow volume flux for the 1995–2005 period. The kinematic overflow flux, defined solely from the velocity field, was found to have an average value of 2.1 ± 0.2 Sv with a seasonal and with inter-annual variations of approximately 10% amplitude, but with no discernible trend for the whole period. The average flux of water with potential density exceeding 27.8 kg m⁻³ was found to be 1.9 ± 0.3 Sv with average properties: θ = 0.25 °C, S = 34.93, γ_θ = 28.01 kg m⁻³ for this period. No evidence was found for a weakening overflow flux, but the salinity of the FBC-overflow, especially the warmer parts, has increased substantially during the period, which implies an increased average density on the order of 0.01 kg m⁻³. Previous observations of a helical cross-channel circulation are confirmed and may explain the thin pycnocline layer, but shear-instability induces intensive mixing that puts a lower limit on the layer thickness. Critical control at one point of the sill cross-section, rather than friction, seems to govern the overflow dynamics and simple layered models can explain much of the observed features as well as the seasonal variation, but potential vorticity, as defined for a single overflow layer, is not conserved. A previously suggested 1950–2000 weakening of the FBC-overflow, which was partly based on a subset of the data presented here, is not supported by the full dataset.     

Oil spill fishery impact assessment modeling: The fisheries recruitment problem

A model to assess the impact of oil spill on fisheries, consisting of an oil spill fates model, a continental shelf hydrodynamics model, an ichthyoplankton transport and fates model, and a fish population model, has been applied to the Georges Bank-Gulf of Maine region to estimate the impact of oil spills on several important commercial fisheries. The model addresses direct impacts of oil on a fishery through hydrocarbon-induced egg and larval mortality. This early life stage mortality is estimated by dynamically mapping the spatial intersection of the surface and subsurface oil concentrations resulting from the spill with the developing eggs and larvae. Ichthyoplankton entering an area with hydrocarbon concentrations in excess of a specified threshold are assumed lost. Model output is given in terms of differential catch, comparing the non-impacted and the hydrocarbon impacted fisheries. Difficulties in establishing stock-recruit relationships, and the inability to predict first year survival even one year ahead make the quantification of absolute catch losses impossible. Output of the model system discussed here is therefore limited to relative rather than absolute catch losses.The paper is organized to demonstrate first the importance of the recruitment question to impact estimation, second that a modeling methodology is necessary to evaluate impacts given the magnitude of unexplained observed recruitment variability, and third a stochastic solution to the problem which places impact estimates in the context of a probability distribution. Lastly, the model system is applied to the problem of attaining better early life history mortality estimates, to ultimately improve impact estimation capabilities.     

Reply to comments by H. Mashima on ‘Evolution of the eastern margin of Korea: constraints on the opening of the East Sea (Japan Sea)’ by Kim et al. [Tectonophysics 436 (2007) 37–55]

We thank H. Mashima for his interest in our recent article in Tectonophysics [Kim, H.J., Lee, G.H., Jou, H.T., Cho, H.M., Yoo, H.S., Park, G.T., Kim, J.S., 2007, Evolution of the eastern margin of Korea: Constraints on the opening of the East Sea (Japan Sea). Tectonophysics 436, 37–55.] and welcome the opportunity to respond to his comments. In our article we suggested that the southern part of the East Sea (Japan Sea) opened principally in the southeast direction in response to the northwestward subduction of the Pacific Plate beneath the Japan Arc. In contrast, Mashima claims that the opening of the East Sea was achieved in the south–southeast direction. However, there are many crucial things in his comments that we find scientifically unconvincing and misleading. In this reply, we give a detailed response to his comments.