东北寒冷地区高等级公路软土地基沉降计算与分析

东北地区的软土地基沉降除了具有变形大、不均匀沉降大、沉降稳定历时较长的特点外。受地质和气候因素影响也较大，这极大地影响了道路的长期稳定和安全使用。这里结合塑料板排水法在东北寒区高等级公路软土地基处理中的应用研究课题，利用哈尔滨绕城高速公路软土地基沉降观测资料，分析了影响沉降的主要原因，利用二种计算方法对软土地基进行沉降计算井做了讨论分析，得出较为符合工程实际的结论。     

石灰碎石桩处理软土地基设计

针对路堤填筑在稻田地基上的情况,为避免路基产生长期不均匀沉降,保证本段路基填土质量,采用石灰碎石桩措施进行处理。     

黄土状地基土浸水后的沉降分析及补强加固

黄土状地基土受到水浸后,沉降变形由湿陷变形和压缩变形2部分组成,其中湿陷变形是产生不均匀沉降的主要原因,文中介绍了水浸后地基土的沉降计算,并对不均匀沉降地基进行补强加固处理。     

肇庆新区某工程软土性质分析研究

指出了肇庆新区位于西江北岸冲积平原,地貌类型为西江河流冲积平原区,软土发育,具有高压缩、低强度、易触变等特性,工程性质差,自重固结或在上覆填土作用下出现不均匀沉降,属不良地基土,对桩基础、基坑工程、市政道路乃至地坪稳定有不利影响。以肇庆新区某工程为例,通过工程钻探、土工实验、原位测试等方法分析了软土发育特征及其工程性质,研究了其固结沉降特征,提出了相应的工程处理建议措施。     

承重墙体沉降裂缝的加固处理

承重墙体出现裂缝的原因是多方面的,本文针对地基不均匀沉降使墙体产生裂缝,结合工程实例,说明裂缝处理的施工过程及采取的补强方法。     

墙下筏片基础的实用计算法

当建筑物上部结构荷载较大、地基承载力较低、墙下条形基础的底面积占建筑物平面面积较大比例时,宜考虑选用扩大基底面积的整片筏式基础。筏片基础具有减小基底反力,提高地基承载力和调整地基不均匀沉降的能力。墙下筏片基础广泛用于量大面广的多层或中高层住宅、办公楼等民用建筑。     

碎石桩法处理软土地基在公路工程中的应用

在软土地基进行工程建筑时，常常会遇到两方面的工程地质问题，即地基土的承载力不足和建筑物产生过大的沉降。特别是旧路改建工程，由于软土孔隙比大、渗透系数小、沉降稳定时间长、很容易造成新旧路堤的不均匀沉降，因此，需要采取相应的治理措施。从工程实际出发．较为系统地阐述了碎石桩法在公路工程中处理软土地基的加固机理、设计方法，并采用应力面积法对加固前后地基土的最终沉降量进行了计算，同时采用了砂井地基的固结理论着重分析了碎石桩法对软土地基渗透固结的影响。     

复合双曲线法预测公路沉降探讨

通过施工填土早期的沉降观测资料来推测设计填土高度下的最终沉降量，是在公路工程中急待解决的课题。现提出复合双法来解决这一问题，即利用早期的填土期实测沉降资料对传统双曲线法进行改进，假定地基土为线弹性变形，并考虑实际土的非线性影响，引入一经验修正系数，来推算设计填土高度下的路基最终沉降量。     

多层建筑承重墙体沉降裂缝的补强处理

承重墙体出现裂缝的原因是多方面的,本文针对地基不均匀沉降使墙体产生裂缝,结合工程实例,说明裂缝处理的施工过程及采取的补强方法,并收到了较好的效果。     

浅谈砖混房屋的裂缝

从材料特征因素、施工因素、地基不均匀沉降因素、环境温度因素、设计因素等几方面分析了北方多层砖混房屋墙体产生裂缝的原因。并从设计、施工及管理维修的不同角度提出了预防和处理裂缝的方法。     

地基基础不均匀沉降原因分析

作者依据工程实例,详细分析了地基基础发生不均匀沉降的种种原因,为工程设计人员更好地搞好地基设计方案,起到了一定的借鉴作用。     

哈尔滨机场高速公路路面结构比较分析

本文对两种半刚性基层材料抗压强度、抗压模量、劈裂强度、劈裂模量等力学特性及干缩、温缩特性进行了分析，并确定哈尔滨机场高速公路采用的方案。     

金叶含笑叶片基因组DNA提取方法的比较

以金叶含笑叶片为实验材料,分别采用CTAB法、改良CTAB法、简易提取方法、高盐沉淀法和SDS法5种方法提取金叶含笑叶片的基因组DNA,并通过琼脂糖凝胶电泳、紫外分光光度计及ISSR扩增3种方法对所提取的DNA样品进行检测.DNA纯度、含量比较以及扩增结果表明:5种方法中简易提取法和SDS法提取的DNA纯度较高.高盐沉淀法得到的DNA产量较高.5种方法提取的DNA用于ISSR扩增,其扩增结果基本一致.简易提取方法操作简单.省时省力,是用于ISSR扩增的金叶含笑基因组DNA提取的最佳选择.     

高浊度水体静沉降特征研究

运用重复深度吸管法测量了水质自动监测站内沉砂池不同时间点的浊度，探析了浊度随时间的变化规律以及高浊度水体的静沉降特征。结果表明：在静沉降过程中，浊度随时间的变化符合指数函数曲线，浊度与沉降速率符合logistic函数关系。当浊度较低时（浊度〈50NTU），沉降速率随浊度升高而增大，且增加幅度明显；当浊度较高时（浊度〉50NTU），虽然沉降速率依然是增加的趋势，但是增加幅度趋于平缓。     

Comparative performances of new and existing indices of crown asymmetry: an evaluation using tall trees of Eucalyptus pilularis(Smith)

Over the past 50 years,crown asymmetry of forest trees has been evaluated through several indices constructed from the perspective of projected crown shape or displacement but often on an ad hoc basis to address specific objectives related to tree growth and competition,stand dynamics,stem form,crown structure and treefall risks.Although sharing some similarities,these indices are largely incoherent and non-comparable as they differ not only in the scale but also in the direction of their values in indicating the degree of crown asymmetry.As the first attempt at devising normative measures of crown asymmetry,we adopted a relative scale between 0 for perfect symmetry and 1 for extreme asymmetry.Five existing crown asymmetry indices(CAIs) were brought onto this relative scale after necessary modifications.Eight new CAIs were adapted from measures of circularity for digital images in computer graphics,indices of income inequality in economics,and a bilateral symmetry indicator in plant leaf morphology.The performances of the 13 CAIs were compared over different numbers of measured crown radii for 30 projected crowns of mature Eucalyptus pilularis trees through benchmarking statistics and rank order correlation analysis.For each CAI,the index value based on the full measurement of 36 evenly spaced radii of a projected crown was taken as the true value in the benchmarking process.The index(CAI_(13))adapted from the simple bilateral symmetry measure proved to be the least biased and most precise.Its performance was closely followed by that of three other CAIs.The minimum number of crown radii that is needed to provide at least an indicative measure of crown asymmetry is four.For more accurate and consistent measures,at least 6 or 8 crown radii are needed.The range of variability in crown morphology of the trees under investigation also needs to be taken into consideration.Although the CAIs are from projected crown radii,they can be readily extended to individual tree crown metrics that are now commonly extracted from LiDAR and other remotely sensed data.Adding a normative measure of crown asymmetry to individual tree crown metrics will facilitate the process of big data analytics and artificial intelligence in forestry wherever crown morphology is among the factors to be considered for decision making in forest management.     

Sedimentation in Mangrove Forests

The tidal currents in mangrove forests are impeded by the friction caused by the high vegetation density. The tidal currents are also complex comprising eddies, jets and stagnation zones. The sediment particles carried in suspension into the forest during tidal inundation are cohesive, mainly clay and fine silt, and form large flocs. These flocs remain in suspension as a result of the turbulence created by the flow around the vegetation. The intensity of sedimentation is largest for trees forming a complex matrix of roots such as Rhizophora sp. and smallest for single trees such as Ceriops sp. The flocs settle in the forest around slack high tide. At ebb tides the water currents are too small to re-entrain this sediment. Hence the inundation of coastal mangrove forests at tidal frequency works as a pump preferentially transporting fine, cohesive sediment from coastal waters to the mangroves. Mangroves are thus not just opportunistic trees colonising mud banks but actively contribute to the creation of mud banks.     

林业土壤有效磷测定方法的应用研究

应用改革后的氢氧化钠－草酸钠沉淀法和快速法，测定尾叶桉、湿地松和杉木林地土壤有效磷与林分各生长量及叶片含磷量的相关性，均明显地高于几种常规方法；测定广东省３０００多个各种类型林业土壤有效磷，均具有检测灵敏度高，不出现零值，脱色好，操作方便的酸性、中生和碱性林业土壤有效磷的结果，亦说明沉淀法和快速法可以测定酸性、中性和碱性各种类型林业土壤有效磷，特别是对测定南方以酸性土为主的各类型体业土壤有效磷效果     

四种含笑叶解剖性状与抗旱性的研究

对2年生乐昌含笑、金叶含笑、阔瓣含笑和深山含笑等4种含笑叶片组织解剖性状的测定与盆栽抗旱性观测表明:供试树种间叶解剖性状在叶片厚度、角质层厚度、栅栏组织厚度、海绵组织的厚度、栅栏组织与海绵组织的厚度比、叶片结构紧密度、叶片结构疏松度和气孔密度等指标有显著差异;上表皮和下表皮厚度结构指标差异不显著.叶片厚度、角质层厚度、栅栏组织厚度、栅栏组织与海绵组织厚度的比值、叶片结构紧密度和气孔密度等值越大的含笑,受旱危害愈轻,其抗旱性就越强.叶片厚度、尤其是角质层的厚度和海绵组织厚度是评价供试含笑抗旱性的重要解剖指标.依据叶解剖性状结构指标,并结合盆栽试验旱害观测,供试树种的抗旱性大小为:阔瓣含笑>深山含笑>金叶含笑>乐昌含笑.研究结果与大田容器苗受持续秋旱产生的旱害观测结果吻合,为苏南地区北移引种提供了科学依据.