万县长江三峡库区塌岸的数值模拟分析

在分析砂、泥岩特性的基础上,通过离散元数值分析,研究了万县长江库岸危岩在不同工况下的稳定性,直观地揭示出危岩在不同工况下的破坏程度,得出危岩的主要破坏形式为倾倒式崩塌,并总结出危岩的大规模破坏发生在蓄水回水期,为三峡危岩治理的对策及时间提供了有价值的参考.     

黄河公伯峡水电站水土流失预防及治理技术初探

结合黄河上游公伯峡水电站建设具体情况,针对该区域内独特的地质、土壤和气候条件,在主体工程和辅助工程施工区内,划分出了不同的治理区域。在分析该区水土流失成因的基础上,采取工程治理和植物治理相结合的方法,提出了适合该区域内的主要治理措施,为黄河上游同类水电站的开发建设与水土流失治理提供了借鉴。     

张祁公路甘肃段水土保持限制性因素分析与评价

甘肃省张掖市甘州区至青海省祁连县公路工程途径黑河峡谷区、高原草甸区等,地质、地形条件特殊、复杂。通过对设计的水土保持措施等进行分析与评价,发现其措施基本满足研究区防治水土流失的要求,无工程建设的水土保持限制性因素。工程建设较为合理地调配利用了土石方,无远距离调运,弃土分段集中、拦挡堆放;设计了完整、系统的截、排水设施、拦挡设施及植被恢复措施,这些措施在满足主体工程安全的前提下,符合研究区预防和治理水土流失的要求,可有效降低工程建设对研究区生态造成的破坏。     

省道S211线危岩病害的研究及处治

危岩是公路工程项目中常遇到的地质灾害问题，它常以突然性和不可预测性在瞬间失稳，对公路的运营和公路上行驶车辆的安全造成危害，因此对于危岩的处治极为重要。在治理过程中，需要对公路边坡的地质情况，危岩的发育成因，做出较为透彻的研究。在设计过程中，往往要根据不同的危岩类型，给出不同的设计方案。     

紫金山金铜矿东南矿段B块地质灾害分析

以福建省上杭县紫金山金铜矿东南矿段B块B1、B2排土场边坡为研究对象,根据气候、地形、地质条件等,采用极限平衡法,分自重、自重＋地下水作用力、自重＋地震水平惯性力3种荷载组合,进行边坡稳定性分析,结果表明,正常条件下排土场边坡处于极限平衡一不稳定状态,当发生暴雨或地震时处于不稳定状态。排土场边坡治理建议采取削坡减载、截排水、坡面减蚀以及生物措施等,并加强对边坡沉降位移的长期监测。     

四川省屏山县县城新址地质灾害分布、形成条件与防治

四川省屏山县县城新址位于真溪乡丁发村,地质灾害主要有崩塌(危岩)和滑坡,分析了屏山县县城新址的崩塌(危岩)和滑坡的分布特征和形成条件,最后提出了防治措施,为后续规划和施工提供了建议。     

资阳地区21世纪水土流失防治措施策略

针对四川省资阳地区地质条件恶劣、植被破坏、水土流失严重的现状,结合远景规划,提出２１世纪水土流失的防治措施战略。对坡面水土流失治理采取调整林木结构、注重发展名优特水保经济林;对大于２５°的坡地退耕还林还草,实行封禁治理;大力发展以坡改梯为重点、骨干蓄水池为中心、“沟、凼、池、井、园、机”相配套的坡面工程治理;推行水平带状耕作、垄作和秸秆覆盖等耕作措施。对开发建设项目,根据项目特点及自然条件,采取修筑拦渣、护坡、土地整治、防洪、泥石流防治等工程和采取绿化措施。     

河套灌区盐碱化的特点分析和治理措施的探讨

本文主要分析了内蒙古河套灌区土壤盐碱化的特点;探讨了盐碱地治理的主要措施;指出在气候干燥,蒸发量大,灌溉水盐份高,用量多,排水少,地下水具有地质矿化源和水位浅以及土壤质地较砂等因素的影响下,河套灌区的土壤盐份具有积累快,年中变化大,含量高等特点。由于盐害最严重的时期是从春小麦播种到5月中旬,本文提出河套灌区盐碱地的治理应首先搞好合理灌水和完善排水;同时改进传统耕作方法,采用先进耕作技术和其他措施综合治理。但任何经济有效的措施的设计与实施都需通过对当地盐碱化过程的深入研究,建立关键时期(秋浇、结冻到化冻、春播)的土壤水盐运动模型,进行田间主体工程的定点试验。     

三峡水库区某滑坡特征和稳定性分析

三峡水库区地形条件、自然地质条件复杂是我国地质灾害的多发区及重灾区。三峡大坝的兴建在一定程度上改变了原有地质环境的脆弱平衡状态,加剧了地质灾害的发生。在研究三峡库区某滑坡的工程地质条件及滑坡体基本特征的基础上,分析了诱发坡体失稳的主要因素,并对该滑坡在四种不同工况下的稳定性进行了验算,验算结果表明,该滑坡目前现状条件下处于稳定状态;在库水位蓄水或者库水位骤降情况下,滑坡体将处于整体失稳状态,因此,有必要采取一定的防治措施确保在三峡水库蓄水之后滑坡处于稳定状态。     

乌鞘岭地区高速公路沿线地质灾害发育特征及防治措施

乌鞘岭地区高速公路是国道主干线的重要组成路段。开展高速公路沿线地质灾害研究,将为该区域高速公路沿线地质灾害防灾减灾提供基础依据。通过实地调查和分析,查明了乌鞘岭地区高速公路沿线地质灾害发育特征、时空分布规律及形成条件。结果表明:乌鞘岭地区高速公路沿线地质灾害类型主要为泥石流和不稳定斜坡,其中泥石流灾害具有分布广泛、发生频率高等特点;不稳定斜坡局部或零星分布,且现状危害轻;从时空分布规律上来看,具有条带性和集中性;形成条件包括地形地貌、地层结构、降雨、人类工程活动和地震;泥石流采取合理选线、监测预警、跨越疏导及生态恢复的防治措施;不稳定斜坡采取优化坡面形态、排水措施、工程治理结合植物防护的防治措施。     

Controlling Acid Drainage in a Pyritic Mine Waste Rock. Part I: Statistical Analysis of Drainage Data

Field experiments were conducted to evaluate the relativeeffectiveness of several covers and amendment techniques forpreventing or controlling acid generation in a pyritic minewaste rock. The covers and techniques consisted of water cover,soil cover, wood bark cover, limestone addition and phosphaterock addition. Water quality data (pH, sulphate, zinc and ironconcentrations) obtained from the experiments were analyzedusing two-way ANOVA (analysis of variance) with repeatedmeasurements. A 5% test of significance (p-value of 0.05) wasused in the analysis. The results suggested that the covers andamendments should be either compared on a time-by-time basis orgrouped into four, based on their performance: (i) water cover, (ii)1% and 3% limestone, (iii) clay, 1% and 3%PO₄, andcontrol (no cover), and (iv) wood bark. The results did not showany significant difference between the drainage quality from1% and 3% limestone-amended rocks. The drainage quality from the 1%and 3% phosphate and clay-covered rocks did not significantlydiffer from the control (unamended) rock. Water cover was foundto be the most effective, while the wood bark cover proved to bean ineffective method for controlling acid drainage in the wasterock. The statistical analysis also showed good replication inthe experiments, as no significant difference in the quality ofthe drainage from the replicates was observed.     

走马岭隧道围岩变形监测及工程地质评价

基于隧址区地质环境条件的复杂性,有必要进行施工围岩变形监测。系统地介绍了隧道围岩变形监测的原理和方法分析;并以走马岭隧道施工过程的深部围岩变形监测为依据,获取围岩动态综合信息以分析围岩变形规律,指导施工;提出围岩变形监测为隧道大变形预测、优化二次支护时间等提供科学依据和施工建议,是岩土工程信息化设计、施工的重要手段。     

Factors and processes of gibbsite formation in Northern Thailand

Gibbsite is usually considered as end product of weathering in tropical environments with potentially high leaching rates. However, there are also hints towards gibbsite formation in initial stages of weathering in different climates. This study reports on a systematic approach based on soil forming factors in order to research the conditions of gibbsite formation in northern Thailand highlands. Therefore, three major study sites were chosen, which differ with respect to parent rock, relief, climate and vegetation. The results show that gibbsite is common in soils of the area. Reasons for its occurrence in soils are manifold. It can be a heritage of the parent rock, a result of initial weathering under free draining conditions or an accumulation under intense chemical weathering caused by high rainfall. Especially the investigation in granite and gneiss areas with a high share of primary minerals indicates that gibbsite can be an early and direct transformation without intermediates from micas and feldspars if free drainage is assured. With progressing soil genesis clay formation reduces drainage and favours kaolinite formation. Only sites with extremely high rainfall and low evaporation (high elevations in northern Thailand) show again a dominance of gibbsite in the clay fraction throughout the whole soil profile.     

焉耆盆地水资源开发与土壤次生盐碱化防控研究

焉耆盆地水土资源丰富,光热条件充分,是新疆农牧业生产的主要基地之一。但由于长期以来水土资源开发不当,导致本区土壤次生盐碱化日趋严重,严重影响了当地农业的持续发展,且其农业排水直接导致博斯腾湖的水质劣化。本文在分析区域土壤盐分分布的空间特征和土壤次生盐碱化产生的背景条件的基础上,提出了区域水土资源可持续开发的对策,并着重分析在该盆地细土平原带通过竖井灌排开发地下水以降低地下水位的必要性与可行性,从而推动该区农业的稳定发展和环境质量的逐步好转。     

尾矿库坝体加高方案排水分析

采用有限元计算分析软件ADINA,建立加高方案渗流分析模型,对渗流场进行数值分析。通过反演分析得到的材料渗透系数远大于室内试验值,加高后浸润线普遍升高。由实测水头值反演获得的渗透系数综合考虑了工程现场条件,此渗透系数作为加高方案的材料渗透系数是合理的。加高后尾矿坝浸润线升高,必须加强防渗排水措施,最好在加高后加设浸润线观测措施。     

喀斯特流域枯水资源遥感反演

喀斯特流域是由独特的地貌、水系结构及水文动态过程组成的地域综合体.影响喀斯特流域持水供水能力的因素复杂多样,除岩性、地貌、植被等因素外,喀斯特流域地貌特征也是影响喀斯特流域持水、保水和供水的重要因素.根据贵州省ASTER影像,利用RS和GIS技术,提取了DEM数据.以DEM数据、TM影像和CBERS影像为基础,选取28个喀斯特流域,分析了影响喀斯特流域持水供水的十大因素,并进行量化处理.借助MATLAB和SPSS软件进行数据处理和分析,构建了喀斯特流域枯水资源遥感反演模型,通过方差分析和样区检验,取得了很好的识别效果.     

Salt accumulation and its control on the plains of Central Asia

The water-salt budget on the plains of Central Asia in natural conditions and under significant anthropogenic impact (irrigation and construction of hydraulic engineering systems) is analyzed. It is shown that up to 87.2 million tons of salts are annually transported to the plains of Central Asia from the surrounding mountains. Under natural conditions, the larger part of the salts was discharged into the Aral Sea, Balkhash and Issyk-Kul lakes, and into deep closed depressions (Tuzkan, Sarykamysh, and others). Thus, these salts were generally excluded from the geochemical turnover. Only 40% of the salts entered the deposits and groundwater of the plains. Irrigation has transformed the water-salt budget in the area. The input of salts into the groundwater and soils increased by 30% and induced the development of soil salinization in the region. Measures for salinization control are suggested. It is necessary to stop the discharge of drainage water into the rivers and the use of saline water for irrigation purposes. The existing irrigation systems should be reconstructed, and the irrigated areas should be reduced.     

Controlling Acid Drainage in a Pyritic Mine Waste Rock. Part II: Geochemistry of Drainage

Mine waste rock can produce acid rock drainage (ARD) when constituent sulphide minerals (for example, pyrite) oxidize upon exposure to the atmosphere. Outdoor experiments were performed to test techniques for preventing and controlling ARD in a pyritic mine waste rock. The experiments involved lysimeter (plastic drum) experiments in which the crushed (25–50 mm particle sizes), amended and unamended waste rock was exposed to natural weather conditions (rain, drying, freezing and thawing) for 125 weeks. The amendments consisted of separately covering the waste rock with compacted soil, wood bark and water and mixing with limestone and phosphate rock at 1 and 3%. Waters draining the various rocks were collected and analyzed for acidity, pH, sulphate and metals. In general, concentrations of SO₄ ^2-, Fe, As, Cu, Al and Mg in the drainage from the control rock increased gradually in the first year, peaked in the second year and increased further in the third year, reflecting increasing acid generation with time. SO₄ ^2- displayed strong positive correlation (0.91 to 0.98) with Al, As, Cu, Fe and Mg.Concentrations of Zn, Mn and Cd reached their maximumin the second year. Geochemical analysis of thecomplete water quality data using the equilibriumspeciation model WATEQ4F suggested waste rockoxidation was most likely controlled by Fe³⁺. Al, SO₄ ^2- and Fe concentrations in thecontrol rock appeared to be controlled by alunite(KAl₃(SO₄)₂(OH)₆), jarosite(KFe₃(SO₄)₂(OH)₆) and amorphousferric hydroxide [(am)Fe(OH)₃] during the firstyear. Ion activity product data (log IAP) forFe³⁺ and OH^- generally ranged between –37and –34 in the first two years but decreased to –39and –40 in the third year, suggesting that amorphousferric hydroxides were beginning to crystallize intomore stable forms such as ferrihydrite (Fe[OH]₃)and goethite (FeOOH) in the third year. The addedlimestone lost its effectiveness after a while,probably because of precipitation of secondaryminerals on the limestone particles. The phosphaterock could not sustain the drainage pH above 6 andlost its effectiveness before the limestone did. Underthe conditions of the experiments, the soil cover didnot work as expected, probably because of sidewallpassage of oxygen and water. The water cover was themost effective control method, reducing the acidproduction rate data from 41 to only 0.08 mgCaCO₃ week^-1 kg^-1 waste rock. The wood bark was theworst performer and accelerated acid production by 170%.     

沟塘组合除涝工程设计方法与应用

鉴于极端降雨事件增加和流域下垫面改变抬高排涝模数对传统沟道除涝工程形成挑战,该文结合塘堰滞涝功能提出了沟塘组合除涝工程技术及其设计方法。基于水文资料缺乏小流域的涝水形成规律,离散设计暴雨历时并假设离散时段内流量过程线符合三角形分布下,采用改进SCS模型和小流域汇流方程推求涝水流量过程线;采用水位-容积关系和堰流公式进行质量平衡演算设计塘堰工程规格。在淮北平原低洼区的农沟和斗沟尺度上组合堰宽分别为0.6和2 m的塘堰工程发现,3、5和10年一遇24 h设计暴雨下涝水流量峰值减少了25%以上,延迟了0.5~1 h,3或5年一遇设计暴雨除涝能力排水沟的除涝标准可分别提高到5或10年一遇。沟塘组合除涝工程为缓解排区和下游区域洪涝压力提供可选方案。     

干旱半干旱区不稳定耕地分析及退耕可行性评估

受不利的自然条件等因素影响,西北干旱半干旱地区耕地稳定生产和可持续生产能力较弱。基于全国不稳定耕地调查评价成果,系统分析了地区不稳定耕地现状、成因,并进一步以新疆尉犁县为典型案例,建立基于生态约束强度的多情景模拟方法,设置生态安全情景、综合协调情景和耕地保护情景三种不稳定耕地退耕情景,模拟地区不稳定耕地退耕前后土地用途调整及退耕规模,在此基础上评估不同情景下不稳定耕地退耕影响及退耕可行性。研究发现,①西北干旱半干旱地区存在510021.53 hm2不稳定耕地,集中分布于新疆北部、甘肃中东部和宁夏中南部,以旱地、水浇地为主的地类结构及较低的耕地质量导致不稳定耕地利用状况普遍不佳;②土地荒漠化、沙化是地区不稳定耕地形成的主要原因,草原、林区和内陆河道过度开垦也是造成地区耕地不稳定的因素;③三种退耕情景下,尉犁县棉花产量将分别下降28.64%、20.34%和10.43%,农民短期棉花种植收入虽受到严重影响,但考虑到退耕后土地用途调整带来的林果业等长期收入,农民总收入将分别增长10.41%、12.01%和15.25%,退耕也有利于改善地区生态环境,地区生态系统服务总价值分别增长26743.05万元、19559.81万元和15147.52万元,综合权衡下尉犁县不稳定耕地退耕具有可行性。西北地区需要制定严格的法律法规限制土地的无序开垦,尽快出台区域生态红线等管制制度,促进土地利用与生态保护达到协调一致。