HYDROLOGIC EFFECTS OF THE FLOOD ABATEMENT PROGRAM IN SOUTHWESTERN OKLAHOMA1

ABSTRACT: Winter Creek is a tributary of the Washita River in south-western Oklahoma. The Soil Conservation Service installed floodwater retarding structures which controlled runoff from 56 percent of a 33-square-mile (8550-hectare) gaged drainage area. Application of a hydrologic model to the flood peaks indicated that the structural treatment reduced the flood peaks an average of 61 percent. The Winter Creek channel has narrowed and deepened since the structural treatment was applied. The severe bank erosion occurring before treatment has been arrested and sediment yield from the watershed has been reduced 50 to 60 percent. In some reaches of the channel there has been a dense growth of trees in recent years.     

THE STABILITY IN WATER OF A NEW CHLORAMINE DISINFECTANT1

ABSTRACT: The stability in water of a novel new chloramine agent, 3-chloro-4, 4-dimethyl-2-oxazolidinone (agent I), which is an excellent water disinfectant, has been compared to the stabilities of several other water disinfectants. The agents tested in addition to agent I included N-chlorosuccinimide, 2, 4-dichloro-5, 5-dimethylhydantoin, tichloroisocyanuric acid, calcium hypochlorite, commercial grade HTH, and household bleach. The total chlorine content of a water solution of agent I in a demand free environment remains constant over a period of at least eight weeks, while that for all of the other agents declines markedly over that time period. An explanation for these observations will be offered. Prior work in these laboratories concerning use of agent I as a disinfectant for lake water in a laboratory scale treatment plant had shown that agent I has considerable potential for use as an alternative to chlorine gas for water disinfection.     

A TECHNIQUE FOR MEASURING RAINFALL POTENTIAL1

ABSTRACT The roles played by thermodynamic stability and precipitable water in the production of rainfall are of prime importance. These two variables have been combined into a “Rainfall Potential” function by the use of multivariate statistical techniques. Data from weather stations in southern New Mexico and southwest Texas were used in the study. The results appear promising for further investigation, possibly in relation to the occurrence of rare but extremely heavy rains     

RELATION OF PHYSICAL AND MINERALOGICAL PROPERTIES TO STREAMBANK STABILITY1

ABSTRACT. Alluvial streambank materials from nine unstable and six stable reaches showed little variation in physical and mineralogical properties. The bulk density of all the samples was so similar that they could be considered from the same population. Particle size distributions showed that the clay fractions were slightly, but significantly, higher for the stable reaches. The mineralogy of all samples was also quite similar. The sand-sized grains of the stable areas were less rounded than those of the unstable areas. This somewhat angular shape of the grains may have produced an interlocking between grains that added stability to the bank material. Also, clay coatings on the sand-sized grains from the stable areas may have caused cementation between grains that also strengthened the material.     

基于岩体扰动参数的边坡结构优化

为了研究岩体扰动参数对边坡稳定性的影响,根据某露天边坡岩体物理性质及坡体钻孔勘探结果,分析了边坡体各岩组在不同扰动参数下的强度弱化过程;考虑由扰动产生的节理裂隙对边坡稳定性的影响,通过Phase^2软件对仿真计算模型进行了不同扰动程度的区域划分;同时提出了一种用于直观表征露天整天边坡稳定性的安全系数“玫瑰花”图。结果表明:各边帮受节理切割和爆破扰动的影响,稳定性差异较大,部分边帮安全储备充足,仍存在优化空间;节理裂隙几何位置对边坡失稳滑移面具有控制作用,对于近乎顺层岩质边坡,其破坏主要沿节理面剪切滑移;对于具有浅埋倾覆节理面边坡,由于岩体强度较高易发生倾倒破坏,所绘制的边坡安全系数“玫瑰花”图可直观表征露天边坡整体稳定性,考虑局部扰动影响对边坡稳定性分析进行精细化表征,为矿山边坡角度的进一步优化提供了一定的参考指标。     

复杂适应系统视角下矿工自制力影响因素研究

为了提高矿工自制力水平、进一步减少煤矿事故中的人因事故,基于复杂适应系统理论及系统动力学知识,通过Vensim PLE软件研究矿工主体与安检人员、环境、工作任务特征3个系统之间的相互作用,并从矿工个体角度构建自制力影响因素仿真模型。研究结果表明:矿工情绪对自制力提升最为显著,疲劳程度对矿工自制力的抑制作用较突出,过高或过低的自信心水平均会对矿工自制力产生削弱影响;因此,改善工作环境、提高整体组织氛围、保证矿工的情绪稳定性以及通过改善作业制度降低疲劳程度对提高自制力最为有效。煤矿企业应根据各因素在工作时间段的不同作用,结合矿工自身生理心理因素,采取相应措施以提高矿工自制力水平。     

某山坡露天矿边坡稳定性的FLAC3D研究

某山坡露天矿,原设计的最终边坡角约为46°。为了探索最终边坡角的合理性,应用快速拉格朗日有限差分法FLAC3D在摩尔-库伦准则下搜索该岩质山坡露天边坡的潜在受拉区,判定其稳定性。结果表明:经济合理的最终边坡角是50°38';应用8 m长的锚索加固局部台阶可减小其潜在受拉区中的拉应力;并段将减小边坡的稳定性;爆破开挖时的同段最大装药量与爆距对边坡稳定性影响明显。该方法确定最终边坡角技术可行,它适用于研究岩质边坡的稳定性,克服了用极限平衡法研究边坡稳定性必须事先假定滑动面的弱点。     

同忻井田地应力测量与回采巷道稳定性研究

为保证同忻煤矿安全、高效开采,采用应力解除法对大同矿区同忻井田3-5#煤层的地应力场进行了测量,结合理论分析、数值模拟与现场监测,分析了在该类型应力场中不同巷道布置方向与巷道围岩稳定性之间的关系。测得同忻井田最大主应力为20.42 MPa,方位角为245.18°,确定了同忻井田地应力场属于σHv型。理论计算和数值模拟的结果表明,有利于回采巷道稳定性的布置方向为与最大水平主应力方向成30°,并采用巷道顶板离层监测仪对其进行了验证。     

基于有限元强度折减法的露天磷矿高边坡稳定性分析

针对尖山磷矿开采实际情况,利用ANSYS有限元分析软件建立了考虑重力载荷作用的高边坡体稳定性分析数值模型,运用强度折减法折减边坡岩体的黏聚力和内摩擦角,根据计算结果分析尖山磷矿东采区高边坡在重力作用下的稳定情况。结果表明:当折减系数由1.33增加到1.34时,高边坡体的位移、塑性应变发生突变,通过边坡失稳的主要判据判定目前尖山磷矿东采区高边坡的安全系数为1.33,边坡稳定。     

地震和降雨作用的矿山排土场稳定性分析

为了研究不同工况对矿山排土场边坡稳定性的影响,在调查分析排土场工程地质特征、散体和地基土物理力学性质、结构特征和稳定性影响因素的基础上,运用极限平衡法对排土场在正常运行、地震、连续降雨3种工况下的稳定性进行了分析。研究表明:3种工况下排土场均处于稳定状态,但在地震条件下排土场边坡稳定安全系数储备较低,可能发生浅层滑坡,对坡脚下部的高压线铁塔和铁路线构成威胁,提出了修筑防滚石挡墙,做好排土场安全监测、排水、日常安全管理工作等对策措施。