混凝土灌注桩的跨孔超声波检测方法研究

通过对跨孔超声波检测方法的理论探讨,结合工程实例,利用声波曲线判定桩身混凝土质量及缺陷的可疑位置,并采用PSD判据法进行辅助分析,从而达到判别桩身缺陷性质及范围的目的。实践证明,采用跨孔超声波法检测混凝土灌注桩桩身质量,其结果直观可靠,为桩身混凝土质量提供了一种有效的检测方法。     

超声波透射法在人工挖孔桩缺陷检测中的应用研究

介绍了超声波透射法检测桩身完整性的基本原理,分析了超声波声学参数与混凝土质量的芜景。通过2根模型桩实测数据判断结果与模型桩缺陷设计进行对比分析,表明超声波透射法能够准确的判断人工挖孔桩的缺陷部位、大小及严重程度等信息,说明超声波透射法是一种行之有效的桩身完整性无损检测方法。     

声波透射法检测对桩基质量的分析与判别

阐述了桩基超声波测试原理,测试方法及应注意的问题。通过超声波几种声学参数的分析,从定性和定量上判断桩身完整性,缺陷位置及缺陷程度。在对桩基质量的判别中,结合几方面综合判定。最后用工程检测实例从定性、定量上判断桩身隋况,并采取相应的处理措施。     

超声波透射法在检测大直径灌注桩完整性中的应用

介绍了超声波透射法检测大直径灌注桩桩身完整性的原理、方法和现场检测技术。通过现场检测实例,给出了基桩存在缺陷时声参量的几种特征。检测结果表明:超声波透射法能够相当准确的判别长桩的多处缺陷。     

超声波透射法在钻孔灌注桩检测中的应用

文章简要介绍了超声波透射法检测钻孔灌注桩质量的基本原理、检测技术和分析方法等，基于对典型实测曲线的分析并结合作者的检测经验，详细描述了应用超声波透射法测桩时的各类桩的缺陷特征。     

灌注桩超声波跨孔法检测技术探讨

超声波中专孔法是以纯纵波声速在无限介质内的传播规律为理论基础,发展起来的一门灌注桩质量检测技术。超声波检测的原理、现场检测、检测过程中应该注意的问题、对检测数据的分析研究和桩身质量判定方法,是章文讨论的重点。     

反射波法检测基桩质量中易误判的一个实例

低应变反射波法是当前广泛应用于单桩完整性检测中最常用的方法之一.低应变完整性检测主要是依据桩身阻抗的相对变化情况来判断桩身完整性,只能进行定性的分析.在实际施工中,因为地质条件与施工工艺千差万别,有时会导致桩身扩径或缩径的情况,致使桩身阻抗发生变化.如果通过这种桩身阻抗的相对变化来检测桩身完整性,容易对桩身质量造成误判.尤其当这种情况出现在桩身浅部时,会因为反射波的尺寸效应而使得测试曲线与实际情况不吻合的现象更明显.结合实际工作中的一个实例,本文中提出在应用低应变反射波法检测时应综合分析地质条件、施工工艺以及现场施工资料,并进行适当的模拟计算,以有效的减少误判.特别是对于桩身浅部的缺陷,应充分考虑到尺寸效应等一些因素的影响而慎重判断.     

反射波法在基桩完整性检测中的应用

桩基础在工程建设中应用广泛,对其进行质量检测十分重要。介绍一种快速,有效的桩基检测方法－反射波法,从检测原理到结合工程实例,阐述其在桩身结构完整性检测中的应用。     

浅谈运用两种方法检测桩身完整性的必要性

简要地介绍了采用低应变反射波法检测桩身完整性的主要原理,说明了该方法的局限性,并结合工程实例强调了用两种方法检测桩身完整性的必要性.     

对粉喷桩质量检测的几点认识

粉体喷射搅拌桩由于具有成本低、工效高、振动小、不取原状土等优点,近年来在软土地区得到采用和推广,取得了较好的工程效果和社会效果。由于该类桩在施工工艺及桩身成型特点与一般混凝土桩灌注不一样,因此,对其桩身质量的检测及其评价也有其特殊性。近年来,临汾地区许多单位应用该类桩基础进行地基加固处理。我们对临汾市扁担巷开发区施工的20栋住宅楼的粉喷桩均进行了钻心取样无侧向抗压强度试验,单桩垂直静载荷试验和桩身质量的低应变动测试验。现以Ⅰ区3号楼的动测情况为主,谈谈我们对该类桩的桩身质量检测的一些看法。     

Landscape diagnosis as a geographical contribution to landscape management

Geographical analysis, diagnosis and prognosis of landscape centre on regional questions. Within this framework landscape diagnosis helps to evaluate capabilities of or hazards to landscape elements or landscape units, starting from an analysis of the equipment of the landscape and of land use patterns, taking into account tendencies of their development. Landscape diagnosis is connected with landscape prognosis, which characterizes conditions and processes of changes in the landscape and contributes to decision making with regard to landscape development. Examples from the densely populated areas round Halle and Karl-Marx-Stadt and the fruit-growing Havel region around Potsdam will serve to show that small-scaled and medium-scaled landscape diagnoses can be developed as secondary diagnoses mainly on the basis of thematic maps, which can then be used in the offices for regional planning in the GDR. Large-scaled landscape diagnoses, however, will be shown as directly derived from field data and as immediately applicable (as a working basis) to landscape management. The synthetic aspect, which takes into consideration the present state and the development of landscape as a whole, will apply to all scales.     

An integration-based estimation approach for the determination of slug test parameters under various flow geometries

A simple parameter estimation procedure, designated as integration-based estimation (IBE), was introduced to determine the hydraulic properties of an aquifer using slug test models subjected to certain flow geometries such as radial and spherical flows. The basic idea behind the proposed IBE approach is to link an integration value at pre-defined normalized head levels for field data with that of a theoretical type curve. The IBE method removes the need for the implementation of the classical graphical matching process which would be ineffective to acquire aquifer parameters for non-ideal aquifer conditions. As the second aspect of this study, a new decision tool was suggested to determine the suitable slug test model to be utilized for the site data since diagnosing the flow character properly is of crucial importance for following a convenient analysis procedure. The estimation performance and limitation of the proposed IBE method were tested for several slug test scenarios including radial and spherical flow models with a number of synthetically generated data sets as well as a field application. Results reveal that the IBE together with the identification methodology not only is able to retrieve aquifer parameters as reliable as the existing techniques in the literature but also diagnoses the flow character precisely as demonstrated in this study.     

突发性强灾害天气预警系统：理论与应用

“突发性强灾害天气预警系统”以WWW为平台,融贯多种天气预报新技术,为各类用户提供了崭新的预报视角和技术含量较高的预报产品;产品包括强对流指数诊断、基于卫星和雷达的外推产品,中尺度数值模式预报产品,以及基于“综合叠套技术”给出的强天气展望和强天气临近概率预报产品等。通过近几年部分省市业务化运行检验,证明该系统整体自动化程度高,运行稳定,其提供的综合预警产品能有效地为暴雨等强对流天气提供预警信息,提高了暴雨等强天气的预报预警服务质量。     

Using ALSM to map sinkholes in the urbanized covered karst of Pinellas County,Florida—2. Accuracy statistics

We apply the logic of clinical epidemiological studies to quantify the accuracy of mapping sinkholes by ALSM in the 750 km² Pinellas County. By such studies, a new diagnostic procedure is tested by comparing the diagnoses in a clinical trial to diagnoses on the same patients from a more reliable, but more elaborate and expensive procedure (“gold standard” in epidemiological context). A relatively undeveloped, 65 km² focus area where we have aerial photographs that are effectively contemporaneous with the ALSM flights serves as the “clinical trial”. The xy-locations in the focus area are the “patients” in the trial. The “diagnostic test” for having “sinkhole disease” is inclusion in a database of sinkhole polygons delimited by ALSM contours (“ALSM-alone”), as detailed in Part 1. The standard of comparison (“gold standard” would be an overstatement in the absence of geophysical testing) is inclusion in a database of sinkhole outlines derived by best judgment of conjunctive interpretation of ALSM and aerial photography. GIS intersections that indicate the sensitivity and specificity of the test (ALSM-alone) are 43 and 98.3%, respectively, and, in the focus area where the prevalence of “sinkhole disease” is 4.7%, the positive and negative predictive values are 55.5 and 97.2%, respectively. Over much of the rest of the county, where only the test can be applied, the prevalence of sinkholes is sufficiently small that it cannot be determined to be any different from zero given the paucity of interpreted sinkholes (positive diagnoses) and the low specificity of the test method. The conclusion, therefore, is that contemporaneous aerial photography is essential to compile an ALSM-derived database that aims to state that the given xy-points lay inside or outside of topographic depressions in the covered karst of west-central Florida.     

A new damsel-dragonfly from the Lower Cretaceous of China enlightens the systematics of the Isophlebioidea (Odonata: Isophlebioptera: Campterophlebiidae)

A new genus and species of isophlebioid, Parafleckium senjituense, is described from the Lower Cretaceous Yixian Formation in China. As it has several significant structures currently considered as typical of either the Campterophlebiidae or the Isophlebiidae, and it helps to clarify knowledge of the morphology and taxonomy of this group of damsel-dragonflies. We propose an emendation of the diagnoses of these two families.     

内蒙古开鲁盆地水文地质实体结构分析与判识

本文根据大量的野外地质钻探、水文地质试验、岩性调查等资料 ,从区域地下水形成的地质条件入手进行分析。查明了研究区第四纪地质实体各期岩相古地理、沉积构造特征、地层空间结构、沉积物粒度的空间变异 ,据此进行了地层分区。为研究区含水层系统的分析与辩识 ,研究垂向水交替 ,准确测定有关参数提供可靠的地质依据。     

川中东北部地区须家河组储层发育主控因素分析

川中东北地区须家河组储层虽然在整体上属于低孔～低渗储层,但在局部仍然发育孔渗相对较好的优质储层。这里通过对沉积作用、成岩作用,以及破裂作用如何影响储层发育程度等方面进行研究,探讨并分析了须家河组优质储层的形成条件与影响因素。研究区须家河组砂岩属辫状河三角洲沉积体系,以发育水上、水下分流河道为显著特征。储层经历了较为复杂的成岩演化过程,受多种成岩作用综合影响。研究认为:沉积相是研究区须家河组优质储层形成的基本条件,岩性是优质储层形成的物质基础,成岩作用是优质储层形成最重要的控制因素,而裂缝是优质储层形成的关键。     

大陆造山带地球化学研究：Ⅰ 岩石构造环境地球化学判别的改进

本文讨论了如何改进岩石构造环境的地球化学判别方法及其应用于研究造山带构造演化的问题，在论述了岩石地球化学特征与形成构造环境关系实质的基础上，提出了优选判别指示元素，参数和方法的准则及应用实例；并提出采用岩套内岩类配套及相邻相造期岩套或岩石建造时空配套综合分析途径的建议，从解决某些岩石化学特征在反映构造环境方面存在的多解性问题，推动造山带构造演化细节的深入研究。     

合肥盆地三尖铺组~(40)Ar-~(39)Ar同位素年代地层学研究

合肥盆地南缘中生代红层层序及时代 ,由于缺乏可靠的化石依据 ,曾几经变动人为因素很大。根据三尖铺组红层中泥岩在沉积或成岩作用条件下形成的伊利石之 40 Ar- 39Ar定年 ,其坪年龄为 15 7.7～ 15 9.5 Ma,等时线年龄为 15 7.2～ 15 9.9Ma,并用 K- Ar法测年进行对比和验证 ,其值为 15 1.8～ 15 5 .8Ma,故确定其时代下限应为中侏罗世晚期 (卡洛维期 ) ,上限可能达晚侏罗世早期 (牛津期 )。40 Ar- 39Ar坪年龄谱还记录了晚侏罗世—早白垩世岩浆活动热事件信息 ,以及三尖铺组红层中陆源碎屑之母岩 (云母片岩及片麻岩等 )形成的冷却史。