厦门地区水土保持适宜草种的筛选研究

通过对适于厦门地区水土保持的草种筛选研究发现，不同的草种生长速度存在较大的差异。经过分析．初步筛选狼尾草、香根草、矮象草作为厦门地区水土保持适选优先草种，宽叶雀稗、阔叶百喜草、窄叶百喜草作为厦门地区水土保持备选草种。     

水库消落带百喜草单混种植适应性研究

红壤区水库消落带植被恢复难度高,目前相关研究较少。文章通过研究在野外模拟红壤区水库消落带水位变化,表明百喜草对水淹环境有较好的适应能力,与岸坡种植无差异;混植香根草后其指标呈现更加稳定甚至叶宽、分蘖数有一定升高的趋势;能够改善土壤酸碱度、提高或稳定有机质、P、N、K含量,具有活化土壤速效养分的性能。单种和混植香根草均可推荐作为红壤区周调节水库消落带植被恢复的植物种,并提供了香根草作为百喜草共生草种的成功案例,针对性提出了减缓低温与水淹叠加效应、混植机理研究等后续研究方向。     

南方红壤丘陵区不同生态恢复措施对土壤质量的影响

对南方红壤丘陵区的荒坡地采取不同生态恢复措施后的土壤理化性质指标进行了测定,分析结果表明:前埂后沟梯壁植百喜草的梯田果园对减小土壤密度、提高土壤持水能力和改善土壤通气状况的效果最好,横坡间种农作物的坡地果园对改善土壤结构效果最好;采取不同生态恢复措施的土壤有机质、全氮、全磷、全钾、速效磷含量均高于裸露地,且以前埂后沟梯壁植百喜草的梯田果园各指标含量最高。采取不同生态恢复措施的土壤碱解氮含量和速效钾含量同样以前埂后沟梯壁植百喜草的梯田果园最高。试验结果表明,采用不同措施的生态果园对土壤的生态恢复效果较好,尤以前埂后沟梯壁植百喜草梯田果园效果最好。     

日本草在南方红壤山边沟果园套种适应性研究

通过对南方红壤山边沟果园套种日本草适应性的研究,发现新开山边沟果园4月套种日本草扦插苗当年的6月分萌数可达6条,8月可达16条,第二年的7月能达11.4条;当年6月干草量可达5 308 kg/hm2,8月达8 523 kg/hm2,比套种百喜草分别低2.61%、13.78%,种植第二年7月达17 333 kg/hm2,比百喜草增加8.33%;当年6月草层厚度可达25 cm,比百喜草低19.35%,当年8月达49 cm,种植第二年7月达46 cm,分别比百喜草高6.52%、2.2%;当年6月覆盖率可达55%,比百喜草低15.38%,当年8月达100%,比百喜草高2.04%,种植第二年7月与百喜草一样达100%;套种日本草当年土壤流失率比裸地减少79.41%,同时能有效改善果园的生态环境.     

不同水土保持措施对坡地养分的影响

对不同水土保持措施对坡地养分的影响进行了研究,结果表明:采取百喜草覆盖或敷盖措施的坡地土壤的养分均得到了提高,养分空间分布差异也明显小于裸露对照,养分空间分布规律为上坡大于中坡大于下坡,横坡方向上养分分布差异不明显,养分有明显的表聚性,速效氮的平面空间分布差异大于有机质和全氮,垂直空间上分布差异速效氮小于有机质和全氮;分析表明采取百喜草覆盖和敷盖措施可以有效提高土壤养分含量并且减小养分的空间分布差异,其中以百喜草覆盖措施效果最好。     

广东省水库消落带几种植物对淹水环境适应性的模拟研究

模拟了周调节水库的消落情况,对几种植物的水淹环境适应性进行评价和筛选。结果表明:周调节水库消落带上单种的香根草、狗牙根、蓉草的各项形态指标均比岸坡未受淹的植株低20%~50%,香根草、狗牙根、蓉草的生长和繁殖受到水淹环境的抑制;百喜草的各项形态指标则与岸坡上的无显著差异,说明百喜草能较好地适应短时间的水淹环境;香根草和百喜草在整个试验期内都保持较高的成活率;经过一段适应期后,香根草和百喜草生长稳定,而随着冬季的到来,香根草和百喜草的生长速度变缓,覆盖率逐渐降低,保持在30%~40%左右,且在春季发芽恢复生长;蓉草和狗牙根在冬季成活率较低,且明显低于岸坡未受淹的蓉草和狗牙根;春季狗牙根能够重新发芽生长,但蓉草复绿较少。总体来看,香根草、百喜草、狗牙根可作为水淹时长较短的消落带的植被恢复备选植物。     

不同地表覆被对赣北柑橘园土壤抗蚀性及产流产沙的影响

为研究赣北柑橘园不同地表覆被措施对土壤抗蚀性及其减流减沙的影响,采用野外径流小区定位观测试验,分析了裸露对照、带状覆盖百喜草、顺坡耕作和横坡耕作等4种措施对土壤团聚体组成、抗蚀性及产流产沙特征的影响.结果表明横坡耕作措施土壤团聚体破坏率最低,其次是顺坡耕作措施.带状覆盖百喜草措施水稳定性团聚体(WSA)含量、干筛与湿筛...     

百喜草——“多用型”水土保持植物

1989年江西首次引种百喜草成功,现已推广面积达2000hm2,并在我国川东、三峡库区,京九铁路两边扎根。百喜草特点: 1、适于立体种植 百喜草株高适中,长约30～40cm、缠结地表的匍匐茎多达40～50枝。 2、具有良好的抗性 高温伏旱期红壤裸瘠地,扦插成活率95％～     

赣南红壤边坡护坡草本植物环境适应性研究

为了优化和筛选出适合赣南地区酸性红壤边坡的护坡草本植物,进行红壤边坡护坡草本植物的环境适应性试验。选择能够在红壤地区生长的7种草本植物(白三叶、黑麦草、红三叶、果岭草、高羊茅、百喜草、四季青),对这7种植物进行室外的播撒试验,根据植物生长特性、红壤特点、成本等,选择了14个指标进行观测。运用层次分析法判断指标权重,再将同一指标下不同种类植物的数据进行归一化,通过在同一指标中的占比大小来判断每种植物的权重,最后结合两组权重综合评价每种植物的环境适应性。结果表明:7种草本植物中黑麦草总体表现最佳且综合权重最大,百喜草和四季青次之,建议选择这3种植物作为赣南地区红壤边坡的护坡草本植物,而红三叶、白三叶环境适应性差、护坡效果一般,不建议作为该地区的红壤边坡的护坡植物。     

红壤坡地覆盖与敷盖径流调控特征研究

坡面径流是造成水土流失的主导因子,控制水土流失的关键是科学调控坡面径流。通过土壤水分渗漏装置(Drainage Lysimeter),探讨红壤坡地覆盖与敷盖径流调控特征。结果显示:不同处理不仅年总径流量存在差异,而且径流分配差异更明显;百喜草敷盖处理年总径流量最大,对照次之,百喜草覆盖最小;百喜草覆盖和百喜草敷盖处理的地表径流远小于对照处理,而地下径流量却超出对照处理许多;年均地表径流与地下径流调配比值百喜草覆盖、百喜草敷盖和对照处理分别为1/51.7,1/35.5和1/1.4。     

EFFECT OF AERATOR ON HYDRAULIC DRAG ACTING ON A CHUTE

The formulae used to calculate the friction in the non-uniform flow chute were examined with the experimental data. and the results show that the accuracy of the formula is enough for engineering applications. A comparison between the results of friction respectively from the uniform flow assumption and the non-uniform flow approximation indicates that the former is an order of magnitude larger than the latter in the case of steep chute. The hydr~3ulic drag on a steep chute with aerators was measured on the hydraulic model directly and the coefficient of the aerator effect on the drag was obtained. The variation patterns of the wall shear just down stream of the aerators were investigated and the mechanism of the increase in the drag by aerator were analyzed qualitatively with the measured water depths just downstream the aerators.     

WAVE FORCE ACTION ON A PIER SITTING ON DEFORMABLE SEABED

In this paper,the seepage action on the bottom of a pier resting on a porous elas-tic seabed is obtained by numerical method.The seabed is assumed to be homogeneous,isotropicand linearly elastic porous medium,and can be described by Darcy's law,and the pore water isassumed to be compressible.The governing equations are Biot consolidation equation and storageequation.Considering the wave force acting directly on the pier,the seepage force and soil skele-ton displacement are computed by iterative calculation with the motion of the pier.In the calcu-lating process,it is divided into a diffraction problem and a radiation problem.Superposition oftwo solutions gives the final result.     

软弱岩基上拱坝加高的可行性研究

采用多种计算及分析手段，对重庆市武隆县木棕河三级电站拱坝加高中面临的主要问题进行分析研究后，最终得出结论：在软弱基础上建坝以及加高坝体，关键在于提高坝基本及坝体弹模，且在经济比较可行的前提下进行相应的措施处理后是可以实现的，该坝加高后的安全运行也证明了其合理性。     

EXPERIMENTAL STUDY ON TOTAL UPLIFT FORCES OF WAVES ON HORIZONTAL PLATES

The total uplift forces of waves acting on horizontal plates are the important basis for the design of maritime hollow-trussed structures. In this paper, an experimental study on the total uplift forces of waves on horizontal plates was conducted by a series of model tests. The results show that the maximum total uplift forces do not necessarily occur with the maximum impact pressure intensity synchronously. On the basis of the test results, formation mechanism of the total uplift forces of waves as well as its influencing factors were analyzed in detail, and an equation for calculation of the maximum total uplift forces of waves on plates was put forward. Lots of test data shows the present equation is in good agreement with the test results.     

EXPERIMENTAL RESEARCH ON EFFECT OF MAIN-FLOW SWING ON FLOW TURBULENCE STRUCTURE

It is mentioned in this paper that the adjustment of flow structure occurs when themain-flow swings.The changes of turbulence structure and flow energy loss in the indoor rivermodel are measured.The experimental data are presented for the first time for the further studyof complicated river flow structure.     

萧山粘土的结构性对渗透性质影响的试验研究

大多数天然沉积的粘土都具有一定的结构性 ,土的渗透性不仅与土的结构性密切相关 ,而且与土的强度、变形有关。土的渗透性是土力学主要研究课题之一。文章对萧山粘土在不同压力下进行原状土与重塑土的渗透试验 ,根据试验结果探讨了粘土的结构性对渗透性质的影响 ,得出一些有实际意义的结论 ,可供实际工程和设计参考。     

ON HYDRODYNAMIC INTERACTION UPON THE WAVE FORCES ON VERTICAL PILE ARRAY

A systematic study is carried out on the hydrodynamic interaction of sin-gle-row vertical pile array with a large number of piles by using the method of wave sourcedistribution.Some new properties for the hydrodynamic interaction among piles are firstreported in this paper.The Present study shows the importance and necessity of reassess-ing the hydrodynamic interaction among multiple objects of large number to reach a com-plete understanding on that subject.     

NUMERICAL STUDY ON EFFECT OF WAVING BED ON THE SURFACE WAVE

1. INTROUCTION There have been lot of researches on the effect of the bottom on the surface wave, in which, most of them involved the fixed bottom with concave, convex, or periodical shapes [1-3]. It seems that very few ones on waving bed are available up…     

ON THE RELATION BETWEEN CAVITATION INCEPTION AND FLOW PATTERN ON PROPELLER BLADES

Oil flow visuallization on the model propellers with and without tripping devices atthe leading edge is revealed in this paper. Roughing leading edge with sand blasting was to simu-late the flow at full-scale condition. The observations of cavitation inception and the detection ofcavitation erosion were made in uniform and non-uniform flow respectively so as to consider theeffects of flow pattern on cavitation inception and to investigate the causes of difference in thelocations of cavitation erosion between model propeller and prototype. In addition, calculationsof the pressure distributions and the behaviour of boundary layer on the propeller blade were alsodone by using theoretical method. It is necessary to gain a better understanding of cavitation in-ception of the propeller.