涪江流域江岸防护林带淤沙固岸效果的研究

在涪江中下游典型江岸营造1000亩淤沙林带,江岸防护林系统经1988年洪水淹后林带内淤积泥沙,在1981年特大洪灾冲成裸露的卵石滩上重新淤地300亩,现已在林间点种农作物;在凸岸营造的淤沙林带,一次洪水淹没后,淤泥沙普遍在20cm以上;凸岸林带内淤沙与乔木胸高断面积成正相关,数学模型:Y=0.0448+0.8558X(Y:淤沙厚度,X:胸高断面积)。当胸径达8cm时,测定单株树干对洪水阻力为6kg,全部冲成倒伏状。凹岸营造固岸林带后,一次洪水淘深河床20cm;固岸林生物工程组合乔草型林网结构与防洪堤水利工程配套后,造成堤与林带区域淤积。     

松北地区粉砂土压实机理初探

影响水泥稳定粉砂土压实度的因素有很多，包括砂的级配、最佳合水量与最大干密度、压实功能及压实方法对压实效果的影响，同时对该种水泥稳定粉砂土的压实机理做了一定的分析。     

The Indoor Experiment Study on Pore Water Pressure Increment and Dissipation of Saturated Sand Caused by Blasting

An indoor experiment on explosive compaction of saturated sand has been done.The changes of pore water pressure during blasting are measured and the laws of pore water pressure increment and dissipation are analyzed.It indicates that the processes of increment and dissipation of pore water pressure have particularity along the depth and radial.At the same time,the development rule of liquefaction under explosive loading is also analyzed;these conclusions obtained in the experiment,may provide some useful references for the engineering design and the theoretic study of explosive compaction for water-saturated granular foundation.     

浅谈稻壳的综合利用与开发

阐述了稻壳资源化利用的途径与方法。稻壳的主要成分是纤维素、木质素和二氧化硅。其纤维素可用于制造木糖醇、糠醛、饲料和肥料等;二氧化硅可用于制造高纯二氧化硅、水玻璃和电池材料;利用它的碳、氢元素,通过热解来获得能源。科学开发与利用稻壳,是保护环境,消除白色污染,发展新能源的有效途径。     

Analysis of Mehcanical Reseponse for Different Physical Property of Reservoir Sandstone

The reservoir sandstone is the sedimentary rock with many cemented sand particles. The different physical property of the reservoir even in the same area results in different mechanical response and sand production of the sandstone. Taking two types of the reservoir sandstones as research subjects, a numerical model based on 3-Dimensional Particle-based Distinct Element (PFC3D) under cylindrical coordinate system was used to simulate the micro-micro response of the sandstone considering the given confining pressure and the oil flow rate. Meanwhile, the sanding initiation and the process of the development were analyzed. The macro stress indicated that the reservoir sandstones with weaker cemented sand particles and less percent of the cemented materials would yield and fail more easily, the sand production was initiated more easily as well. Meanwhile, the stress of the parallel bonds indicated that the reservoir sandstones with granule and less cemented materials dislodged from the sandstone more easily, and the force on the particle contact was larger and the sandstone failure was more serious.Hence, the probability of the dislodged particles flowing into the wellbore was also much more. In addition, the particle displacement and rotation indicated that the physical property of the sandstone played a significant influence on the mechanical response and the sand production, the results also agreed with the above results. Therefore, the sand mechanical response and sand production of reservoir sandstone are both different due to different physical property of the reservoir. As a result, the reliable measures of the sand prediction and sand control will be adopted based on the reservoir physical property and conditions.     

砂土地基上圆形浅基础三维破坏包络面的理论研究

对砂土地基上圆形浅基础在竖向荷载V、水平荷载H及力矩M复合加载条件下的承载力进行了系统的三维有限元分析。在分析中,砂土假定为纯摩擦材料,遵循基于Mohr-Coulomb破坏准则的理想弹塑性本构关系。首先,对圆形浅基础的竖向承载力进行了有限元计算, 并与滑移线解法进行了对比,两种方法所得结果比较吻合。进而探讨了砂土内摩擦角对于基础在V-H、V-M荷载平面与V-H-M三维荷载空间内的破坏包络轨迹的影响。计算结果表明,与不排水情况下软黏土地基上基础破坏包络面相比,砂土地基上圆形浅基础的破坏包络面形状有较大差异, 但V-H和V-M平面内的破坏包络面形状仍具有较好的归一化特性。基于有限元计算结果,建立了圆形浅基础在V-H-M三维荷载空间内的破坏包络面方程, 该方程可用来合理评价复合加载条件下砂土地基上圆形浅基础的整体稳定性。     

陆地棉Dirigent-like基因(GhDIR)的克隆与分析

Dirigent-like基因(DIR)编码蛋白质参与木质素的形成,与植物体的病菌防御有关.本研究以抑制差减杂交( SSH)技术获得DIR的EST为信息探针,对棉花EST数据库进行同源搜索和序列拼接,获得了全长为768 bp的DIR基因cDNA全长,将该基因命名为GhDIR.该基因序列的开放阅读框(ORF)位于70 ～...     

沙埋对毛乌素沙地沙芥和斧形沙芥幼苗生长的影响

为探讨沙生植物幼苗对沙埋逆境的适应机理,以中国特有种沙芥(Pugionium cornutum L.)和濒危种斧形沙芥(Pugionium dolabratum Maxim)为研究材料,取自然生境的沙土,采用人工模拟试验,研究沙埋对沙芥、斧形沙芥幼苗生长的影响。结果表明：遭受沙埋后,沙芥和斧形沙芥幼苗节间伸长的顺序均为T2/3>T1/2>T1/3>T0。沙埋深度在沙芥与斧形沙芥幼苗高度的1/3、1/2时,幼苗存活率100%,地上干重、总生物量、叶面积增长百分率、每天净增加的生物量和每天单位面积所固定的净光合产物均明显高于对照,根冠比显著低于对照;沙埋深度在幼苗高度2/3时,沙芥和斧形沙芥存活率分别为80%、60%,以上各指标均明显低于对照,根冠比显著高于对照;全部沙埋时,均不能成活。本研究说明,沙芥、斧形沙芥幼苗对沙埋具有较强的适应性,当幼苗遭受到沙埋后,沙芥、斧形沙芥延长了节间伸长和分配较多的生物量用于地上部分的生长,这种生长方式和分配模式可能是沙芥和斧形沙芥幼苗对沙埋环境的重要适应对策。     

A Stress Path Damage Constitutive Model for Sang

A hypothesis that the skeleton deformation of sand is only the deformation of the interfaces of grains, and the deformation characteristics including nonlinearity, plastic deformation and shear dilation are controlled by the sliding of interfaces of grains within skeleton, is presented.The contact between grains is classified as perfect contact and sliding contact in this paper.In the elastic deformation phase, the contact between grains is regarded as perfect contact.With the increase of shear stress, there are gradual conversions from perfect contacts to sliding contacts which are viewed of damages in this paper.Based on Mohr Coulomb law, a calculation method for the damage ratio is given according to the relative distance of the stress point to the initial damage line and failure line.On this basis, a damage constitutive model is proposed.The model properties can be conveniently obtained through conventional triaxial compression test and constant stress ratio consolidation test.Test results indicate that the model is capable of predicting deformation behavior for various conditions, including varying consolidation conditions and stress paths.     

木质素/皮胶/聚乙烯复合改良剂对风成沙稳定凋萎含水量影响

本研究旨在利用生物质基材料制备风成沙改良剂并研究其对风成沙稳定凋萎含水量的影响,确定改良剂改良效果最佳时各材料最佳掺量。笔者采用4水平3因素正交试验研究了木质素、皮胶、再生低密度聚乙烯对风成沙稳定凋萎含水量的影响。研究结果表明：3种材料制备的改良剂的加入对稳定凋萎含水量的提高具有显著地促进作用,其中皮胶影响达到极显著水平,木质素和聚乙烯影响不显著;皮胶掺量与土壤稳定凋萎含水量之间具有线性相关性,采用逐步分析法得二者间回归方程相关系数0.962。聚乙烯再生料在风成沙中掺量低于15%(wt%)时对风成沙土壤稳定凋萎含水量具有一定促进作用,超过15%时则会使该指标略有下降。木质素、皮胶、聚乙烯再生料在风成沙中添加比例为10%:20%:15%时,风成沙土壤稳定凋萎含水量达到最大值23.72%,改良剂改良效果最佳。该试验结果可为利用生物质材料改善风成沙保水性的研究提供一定的参考价值。