本文采用综合评价法对北方黑土区振祥流域的3种水土保持治理措施进行对比分析,并对不同措施的生态效益和经济效益进行分析.结果表明,3种不同的水土保持措施在不同方面各有优势,工程措施在经济效益方面最为明显,林草措施和耕作措施在生态效益方面较明显;综合效益分析结果显示工程措施的效益明显高于其他两种措施.基于研究结果,本文从3个方面提出针对性建议.

砂土区淤地坝破坏的主要形式是渗流,在淤地坝的反滤体中运用土壤固化剂能够防止渗透破坏的发生.为探寻一种最优配比的无机固化剂,以陕西省榆林市靖边县沙旋沟淤地坝筑坝土料为例,通过原土料和添加不同配比固化剂土料的渗透破坏试验,对比分析不同配比固化剂的完全破坏临界水力坡降来寻找最优配比的固化剂,并将选出的最优固化剂应用于模型坝的试验中来检验固化剂的实际效果.结果 表明,所有土料渗流流速在渗透破坏前均随水力坡降的增大而增大;添加固化剂降低了土样的渗流流速,增加了土样的抗渗能力和稳定性,其中添加5％的无机复合固化剂土样的效果最好;在模型试验中,添加无机复合固化剂的土料对于“坝后流泥”现象具有一定的修复效果.

黄土高原沟壑纵横,塬面水流在入沟过程中,不断冲刷沟头,导致沟底下切,沟壁坍塌,形成溯源侵蚀.为防止从沟头跌落的水流对沟底冲刷,减缓沟头侵蚀发展,保护塬面,采用柔性防护措施消减水流动能.试验通过覆麦草和土工布模拟柔性防护措施,研究柔性防护措施的消能机理.试验以裸土为对照,测定在高水头冲刷下,不同防护措施的冲刷坑深度、坑径、坑面积及坑容积,定量分析了柔性防护措施的作用效果.结果 表明:随着覆麦草量的增加,冲刷坑深度呈线性递减、容积呈指数递减;而加覆土工布,能显著提升防护效果;在4.93m试验水头冲刷3 min的条件下,覆2 400 g/m2麦草和1层土工布能够完全保护土面不被冲刷.柔性防护措施具有良好的消减水流动能的作用,对防止沟床下切,有效保护塬面,防治沟头侵蚀效果显著.

为阐明生产建设项目回填土边坡抗剪强度与土壤含水量和干密度的关系,以陕西省西安市周至县活龙山研究区土壤(典型黄土)为研究对象,根据实地调查取样,采用击实法制备3个密度梯度、7个含水量梯度的21组供试土样,进行直剪试验,分析土壤干密度与含水量对重塑土抗剪强度指标的影响.结果表明:在密度相同的条件下,重塑土的内摩擦角随着含水量的增加整体呈现下降趋势,当含水量过大时出现小幅跃升现象;土壤内摩擦角随干密度的变化规律不显著.土样粘聚力与干密度呈正相关,与含水量呈负相关,且含水量较低或密度较大时,粘聚力的变化幅度较大.土壤抗剪强度与干密度均呈线性正相关,与含水量呈负相关.说明干密度和含水量对重塑土抗剪强度特性有较大影响;干密度主要通过粘聚力影响抗剪强度,而含水量则通过粘聚力和内摩擦角共同影响抗剪强度.

Seepage failure is the most common damage to the check dam.To explore the effects of polypropylene geotextile bags on seepage failure,and to provide theoretical basis for dam reinforcement,this paper simulated the seepage damage of the dam soil (silty loam) in Jingbian area of Northern Shaanxi.Polypropylene geotextile bags filled with original soil were used as a filter to its effects on the permeation time and phreatic line of the original dam.The results showed that with the occurrence of seepage failure,the water level height in all parts of the two dams gradually increased to a certain stable value,the current area of the soil was saturated.The dam water level from the front of the dam to the back of the dam decreased.Polypropylene geotextile bags filled with soil as the filter not only could slow the rate of water level in the dam parts,but also reduce the maximum height of the water level,thus reduce the phreatic line of dam and slow down the occurrence of seepage failure.

以志丹县的中粉质壤土和杨凌的重粉质壤土作为试验材料,通过室内土工击实试验,求得志丹县中粉质壤土和杨凌重粉质壤土的最大干密度和最优含水率.结果表明:土壤的干密度,随含水率的增加而增加,但当达到一个峰值时,土壤的干密度就随含水率的增加而减小.志丹县中粉质壤土最大干密度为1.689 g/cm3,最优含水率为15.2％;杨凌重粉质壤土的最大干密度为1.740 g/cm3,最优含水率为17.2％.土料含水率在最优含水率前后时,含水率对干密度的影响具有相似性,说明土料含水率在最优含水率前后时,含水率对压实质量的影响具有相似敏感性.可为坝体工程设计和检验成坝质量提供参考的数据.

植被恢复情况是生产建设水土保持监测的主要内容,也是生态环境恢复的重要指标.为高效精准进行植被恢复率计算,应用无人机航测影像数据,利用ENVI非监督分类及目视判别手段,在实现影像土地利用分类的基础上提取植被面积,以期为生产建设项目水土保持监测提供可靠的依据.结果表明:(1)无人机在能见度较高且风速稳定天气条件下,可快速获取小区域地面高分辨率影像.(2)无人机正射影像图在Envi 5.1软件非监督分类的基础上采用目视解释法可实现水土保持土地利用现状分类.(3)通过对各地物分析剖解,在目视判决准则下可划分植被并提取植被面积.(4)利用无人机获取试验区域的正射影像图,其水平精度可达0.2m.高精度无人机遥感数据可用于小范围生产建设项目水土保持土地利用分类及植被恢复分析.

基于单向固结理论,对陕西白水的低液限黏土土样进行了各向等压孔隙水压力消散试验,试验结果表明,土中孔隙水的消散参数与土的物理性质、围压和时间具有较强的关联性,试验结果可靠性强,所得到的孔压消散系数等重要参数对于工程设计和施工具有参考价值.

[目的]以内蒙古准格尔旗黑岱沟露天煤矿北排土场为研究对象,为矿区的植被恢复和治理提供依据.[方法]通过野外土壤剖面调查和采集土壤样品,对9种植被恢复模式及对照区土壤理化性质进行测定和分析,并通过土壤质量指数计算,对不同植被恢复模式下土壤质量进行评价.[结果]各种植被类型均能有效地改良土壤.其中沙棘的容重最小,为1.35 g/cm3;油松+沙棘+锦鸡儿的含水量最大,为13.32％;油松+杨树+柳有机质最高,为9.42 g/kg;油松+沙棘+锦鸡儿土壤速效N和速效K含量均为最高,分别为21.32和90.21 mg/kg;锦鸡儿土壤速效P含量最高,为6.47 mg/kg;沙棘和锦鸡儿作为灌木的乔灌混交模式下土壤质量综合评价值最高,单一种植沙棘以及锦鸡儿的土壤质量综合评价值也较高.[结论]种植沙棘、锦鸡儿以及乔木、沙棘和锦鸡儿的乔灌混交类型对该地区土壤复垦有重要作用.

水坠法修筑淤地坝技术近年来得到了广泛的应用和推广,但流态区的存在使得该技术具有一定的安全隐患,对于流态区位置的探求,常规的土钻法费时费力.以陕西省志丹县前拐沟淤地坝为研究对象,运用静力触探技术,结合SURFER软件作图探求流态区位置,并验证坝体稳定性.采用该方法探求水坠坝流态区位置,具有操作简单、快速精确的特点.

以延安市志丹县前拐沟淤地坝筑坝现场修筑的人工试验小区为研究对象,使用土水比为1.0和1.5的泥浆,进行3种管道布设方式(横向管道、竖向管道、横竖向结合管道)、3种灌浆高度(30、60、90 cm)下的排水管网优选试验.结果表明,横竖结合管道的排水效果最好,竖向管道次之,且二者差距不大,横向管道最差,实际筑坝中宜优先选用竖向排水管道;在布设竖向管道和布设横竖结合管道2种情况下,管道排水均集中在试验最初的12 h内,且同种布设方式管道排水效果受灌浆高度的影响不大,可适当缩短1次灌浆后的静置时间和适当增大灌浆高度以缩短筑坝工期.

泥浆的排水固结变化对水坠坝筑坝过程中坝体排水系统的合理布设具有重要的指导作用.将中粉质壤土以1∶1,1.5∶1和2∶1的土水比制成泥浆,并将制得泥浆分别填充在高度为50,100,150和200 cm的聚乙烯波纹管中,对其排水量、上析水量、下渗水量和固结沉陷量等指标进行测定.结果表明,同一土水比的泥浆,上述指标随着泥浆填充高度的增加而增大;同一泥浆填充高度,上述指标随着土水比的增大而减小.泥浆的排水量、固结沉陷量主要集中于前24 h,排水量最大可占总排水量的89.48％,固结沉陷量最大可占总固结沉陷量的93.24％.因此,在实际筑坝过程中土水比较小时,应注重坝体泥浆的前期排水,并加强表层排水;土水比较大,充填高度较小时,可考虑不布设坝体泥浆表层排水措施,而要加强下渗水的排水措施.

【Objective】To prevent the collapse of terraced ridges in Qinba mountainous area and overcome the limitation in the popularization of ridges built with rocks or concrete,this study focused on the stability of ridges built with polypropylene geotextile bags(PP bags)and investigated the effects of ridge height,slope and rainfall intensity.【Method】PP bags ridges with two slopes,A(slope 65°-70°)and B(slope 70°-75°),were conducted.Each slope had two treatments with and without connecting buckles.Effects of three ridge heights,1.0and 1.2and 1.4m,were investigated,respectively.Anti-shear strength,sliding resistance,overturning force resistance and soil press of each treatment were measured before and after rain.【Result】After heavy rain,shear strength increased as the increase of soil press,in the contrary,anti-overturning strength and anti-sliding resistance coefficient were decreased.Buckles significantly increased the anti-shear strength.Without buckles,the ridges were more likely to collapse,especially in the second or third floor with ridge height of 1.2-1.4m.With buckles,the collapse tended to happen in thethird floor with height of 1.2-1.4m.When the slope was 65°-75°and the ridge height was≥1.2m,sliding was more likely to happen than overturning.【Conclusion】When the ridge height was less than 1.0m,and the slope was 65°-75°,the PP bags ridges were stable while when the slope was 65°-75°and the ridge height was≥1.2m,the ridges were likely to collapse even with buckles.

本文在分析黑麋峰抽水蓄能电站常家冲弃渣场防护条件的基础上，提出了坡脚拦挡、坡面防护、渣顶植被恢复和场地排水的综合防治措施体系，并分别进行了措施设计。该措施体系在常家冲水土流失防治中效果显著，可以作为抽水蓄能电站冲沟型弃渣场水土流失防治的参考。

Taking alfalfa and sainfoin as the main research objects,the soil physical properties,anti-erodibility,anti-scourability and anti-shear strength in and between the forage hedgerows were tested before and after planting hedgerows.The correlations among these factors were also analyzed.The results were as follows:1)Forage hedgerows could significantly improve soil physical properties,including soil bulk,porosity,moisture content and the content of the water-stable aggregates.2)Forage hedgerows could improve the soil anti-erodibility,anti-scourability in sloping land,and anti-shear strength in forage hedgerows was smaller than that between them.3)In forage hedgerow systems,soil anti-scourability was negatively correlated with soil bulk,and positively correlated with soil porosity,moisture content and the content of the water-stable aggregates.Soil disintegration rate was positively correlated with soil bulk,and negatively correlated with soil porosity,moisture content and the content of the water-stable aggregates.

Anti-soil erosion capabilities of terrace hedgerows were examined by static water disintegration test.The relationship between disintegrating quantity and plant roots in different soil depths was analyzed to understand the effects of different terrace hedgerows on anti-soil erosion ability.The results showed that terrace hedgerows could obviously decrease the soil disintegrating quantity and increase the anti-erosion ability of terrace ridges.In the control ridges without plant roots,with the increase of the soil depth,disintegrating quantity decreased for the increase of the soil density.Between the dual effects of root system and soil density,roots were more influential than soil density,disintegrating quantity decreased with the increase of the number of effective roots,and the anti-erosion capability increased.

In order to study the effects of biological crusts forming in different development periods in loess hilly areas on soil anti-erodibility,the differences of soil disintegration and soil anti-shear strength under two different treatments,retention of biological crust and removal of biological crust were analyzed.The results were as followings:(1) the formation of biological crusts can reduce the soil disintegration quantity,with the development of biological crusts,the influence degree improved from 21.85% to 43.46%;(2) the formation of biological crusts can improve the anti-shear strength of soil at the rate of 17.91%~23.45%,and the development of biological crusts has the positive correlation with soil anti-shear strength;(3) soil disintegration quality had the negative linear correlation with soil anti-shear strength.As the biological crust can enhance the soil particle interaction,the effect of moisture on soil particle dispersion was reduced,which made the rate of change of soil disintegration to anti-shear strength reduced.

中华人民共和国国家发展和改革委员会于2007年7月20日发布了DL/T5064-2007《水电工程建设征地移民安置规划设计规范》,较原规范(DL/T5064-1996《水电工程水库淹没处理规划设计规范》)增加了移民安置环境保护与水土保持设计内容,强调了移民安置工程中环境保护与水土保持工作的重要性。农村移民安置工程是水电项目移民安置规划的重要内容,因此,如何做好农村移民安置区的水土保持规划设计非常重要。本文将探讨如何根据农村移民安置区的特点,以"预防为主、保护优先、全面规划、综合治理、因地制宜、突出重点、科学管理、注重效益"为指导方针,制定水电项目农村移民安置工程水土保持规划设计,使工程建设过程中的水土流失得到及时和有效地控制,保证"三同时"的落实。

In order to select the optim al soil-water ratio under the same filling velocity,the research of slurry properties was conducted under two soil-water ratios(2∶1 and 2.5∶1) with a constant filling velocity of 15cm/d.Taking the Lou soil of Yang Ling as the research target,the utilization of the artificial network drainage system in the dam construction with mud pumps,provided foundational material and theoretical guidance for constructing mud dams in the region of heavy silt loam,as well as the scientific basis for the promotion and application of the technology for constructing dams in similar areas.The Lou soil of Yangling was collected,and the PVC pipes with the same height and diameter were used to simulate the layered filling process of damming by mud pumps,lateral drain-pipes were devised to stimulate the drainage system of dams as well.Slurry of two soil-water ratios(2∶1 and 2.5∶1)was prepared,the displacement,and the shear strength,osmotic coefficient and other indicators of the slurry under the constant filling speed(15 cm d) were determined for reflecting the changes of slurry properties.The overall trend of each index of the slurry was consistent under two soil-water ratios and the constant filling speed,but the variance ratio differed greatly.Each index of the slurry with the small ratio of soil-water changed more obviously and regularly than the slurry with the large ratio of soil-water.The dehydraton property,permeability and subsidence quantity of the slurry with the high moisture content changed notably than the slurry with the high ratio of soil-water,however its consolidation and shear strength were weaker.The permeability of the slurry in the lower layer with two soil-water ratios became weaker gradually as the slurry layer was heightened,which was bad for the drainage and consolidation in the later grouting period.According to the generalized analysis of the several indicators,the results suggested that the optimal ratio of soil-water is 2.5∶1,and this research will provide references for the in-situ damming.

农村移民安置工程是水电工程移民安置规划的重要内容。本文探讨如何根据农村移民安置区的特点,以预防为主,防治并重,因地制宜,因害设防为指导思想,编写水电项目农村移民安置工程环境保护规划,寻求科学合理、因地制宜的预防和保护措施,为今后编写水电项目农村移民安置工程环境保护规划提供参考。