廊坊市排水管网污水改造工程

本文详细介绍了廊坊市排水管网污水改造工程中顶管施工试验段的施工技术,从钻前准备、施工设计、设备选型、工作坑施工、顶管施工进行了说明,最后对施工进行了分析总结,给出了施工中存在的问题和施工经验。     

顶管施工工艺浅析

要内随着顶管施工技术的发展,顶管领域出现多种的施工方法,包括泥水平衡顶管施工法、土压平衡顶管施工法、气压平衡顶管施工法等多种施工方法,这些方法有相通点同时也具有各自不同的特点。介绍施工方法的同时,指出几类施工过程中关键技术、质量控制等方面应该注意问题。     

高原多年冻土隧道施工温度场控制的主要因素

施工温度场的控制对于多年冻土隧道的施工有着重要的意义. 结合青藏铁路昆仑山、风火山隧道的设计与施工, 通过对施工过程中环境温度的测试, 综合分析冻土稳定、混凝土施工、施工人员及施工机械等各方面的因素对施工环境温度的要求, 提出了适合于青藏铁路高原多年冻土隧道的施工环境温度控制范围.     

信息化设计施工在机场高填方边坡工程中的应用

信息化设计施工是一种动态的设计施工方法,通过施工过程中的施工信息,掌握工程岩土体的工作状态,从而调整优化初始设计施工方案。本文分析了机场高填方边坡的主要施工信息,提出了信息化设计施工的工作模式,并以西南某机场扩建工程为例,介绍了机场高填方边坡信息化设计施工的实际工程应用。这种设计施工模式在实际工程中取得了较好的应用效果。     

试论烟水配套工程施工组织设计

安顺市西秀区宁谷镇河坝田烟水配套工程位于安顺城东南,距宁谷镇政府3 km。由于工程工期短、工程量大、施工范围广,在施工中,需结合本工程地形、施工条件及工程特点进行施工布置,本着满足施工强度要求、减少施工干扰、方便施工管理,因地制宜、最大限度利用有利因素的原则进行施工。     

厚覆盖层坝基处理工艺中振冲碎石桩的应用探讨

振冲碎石桩工艺目前在地基施工当中具有非常广泛的应用,其施工的速度较快,且对工艺的技术要求比较低,前期的投资成本占比例较低,因而被广泛地应用在目前的坝基施工当中.基于此,本文以凉山州某水坝施工工程为例进行相关的探讨与分析,针对工艺处理中振冲碎石桩的具体应用,详细说明了施工情况,施工工艺,施工原理和施工顺序,分析了施工过程...     

车站风道施工对既有桥基变形的影响规律

以复杂建筑物环境下北京国贸地铁车站风道暗挖施工工程为背景,研究风道施工对既有立交桥梁变形的影响规律,提出可行的施工变形监测方案.研究结果表明,导洞开挖支护施工阶段、风道加固扣拱施工阶段、北风道开挖支护施工阶段是车站风道开挖关键的三大施工阶段.加固扣拱施工阶段对既有桥基的变形影响较大,在此阶段采取加固措施,处理好节点转换问题.在洞桩法施工风道过程中,应采用信息化施工技术,加强桥基、地表和地下风道洞周的变形监测工作,保证风道安全施工.     

基础灌浆施工技术在水利施工工程中的应用研究

针对现有水利施工工程当中存在的牢固性差的问题,对施工工程进行改进,引入基础灌浆施工技术,以提升在水利工程当中的应用效果。通过钻孔取芯、冲洗、压水、灌浆、封孔5个步骤设计基于灌浆施工技术的水利工程施工流程,并在岩溶地形以及严重漏水的工程环境下实现水利施工工程。经过与传统水利施工工程的对比实验发现,传统水利施工工程能够承受的最大压力为500 MPa,而基础灌浆施工技术下的水利施工工程可以承受1500 MPa的压力,由此得出结论:基础灌浆施工技术下的水利工程牢固性更强、质量更高、应用效果更佳。     

公路软基施工质量综合控制方法

根据大量公路软基处理的施工实践,提出了公路软基处理施工质量的综合控制方法。实践表明,从软基处理的施工机械、原材料、施工安排、施工过程、施工效率、成品检验、制度威慑等方面进行公路软基施工质量综合控制是有效的,也是必要的。     

现代城市供水管网施工中常遇问题与解决对策

通过城市供水管网施工中几个常见问题的论述和实例介绍,说明城市供水管网施工是一个涉及面很广的系统工程,应严格按照设计要求和《给水排水管道工程施工及验收规范》进行施工,以保障城市供水管网工程的施工质量和安全运行。并提出要活学活用。依据施工经验,根据实际施工情况,采取一些切实可行的、灵活的变通方式,既降低施工成本叉提高施工效率。     

Nouvelle interprétation tectonique de la montagne Sainte-Victoire (Provence,France)

The explanation normally given for the tectonics of Sainte-Victoire Mountain, a dozen kilometres east of Aix-en-Provence, to the north of the limestone Provence, is incorrect. To the east, the morphology of the Sainte-Victoire is subdued, whereas to the west, before the mountain breaks savagely, the morphology is that of a young mountain as appears in Alpine landscapes. This unusual aspect in the region and the large subvertical faults with vertically striated surfaces that mark the massif to the south and to the west, induce the idea of strong vertical uplifts and caste doubt on the tectonic interpretation given in 1962 by Corroy et al. According to those authors, the Sainte-Victoire is a unit of Jurassic and Cretaceous formations overthrusting 1800 m to the south conglomerates of the Late Cretaceous or Palaeocene. New observations about the conglomerate transgression over the Jurassic and Cretaceous beds, and about the faults around and on the massif do not give evidence of an overthrusting but, on the contrary, induce the idea of a uplift, perhaps still active, in the form of a ‘piano key’ inclined to the northeast. To cite this article: J. Ricour et al., C. R. Geoscience 337 (2005).     

Statistical considerations for grain-size analyses of tills

Relative percentages of sand, silt, and clay from samples of the same till unit are not identical because of different lithologies in the source areas, sorting in transport, random variation, and experimental error. Random variation and experimental error can be isolated from the other two as follows. For each particle-size class of each till unit, a standard population is determined by using a normally distributed, representative group of data. New measurements are compared with the standard population and, if they compare satisfactorily, the experimental error is not significant and random variation is within the expected range for the population. The outcome of the comparison depends on numerical criteria derived from a graphical method rather than on a more commonly used one-way analysis of variance with two treatments. If the number of samples and the standard deviation of the standard population are substituted in at-test equation, a family of hyperbolas is generated, each of which corresponds to a specific number of subsamples taken from each new sample. The axes of the graphs of the hyperbolas are the standard deviation of new measurements (horizontal axis) and the difference between the means of the new measurements and the standard population (vertical axis). The area between the two branches of each hyperbola corresponds to a satisfactory comparison between the new measurements and the standard population. Measurements from a new sample can be tested by plotting their standard deviation vs. difference in means on axes containing a hyperbola corresponding to the specific number of subsamples used. If the point lies between the branches of the hyperbola, the measurements are considered reliable. But if the point lies outside this region, the measurements are repeated. Because the critical segment of the hyperbola is approximately a straight line parallel to the horizontal axis, the test is simplified to a comparison between the means of the standard population and the means of the subsample. The minimum number of subsamples required to prove significant variation between samples caused by different lithologies in the source areas and sorting in transport can be determined directly from the graphical method. The minimum number of subsamples required is the maximum number to be run for economy of effort.     

Evolution of the European Cenozoic Rift System: interaction of the Alpine and Pyrenean orogens with their foreland lithosphere

The evolution of the European Cenozoic Rift System (ECRIS) and the Alpine orogen is discussed on the base of a set of palaeotectonic maps and two retro-deformed lithospheric transects which extend across the Western and Central Alps and the Massif Central and the Rhenish Massif, respectively.During the Paleocene, compressional stresses exerted on continental Europe by the evolving Alps and Pyrenees caused lithospheric buckling and basin inversion up to 1700 km to the north of the Alpine and Pyrenean deformation fronts. This deformation was accompanied by the injection of melilite dykes, reflecting a plume-related increase in the temperature of the asthenosphere beneath the European foreland. At the Paleocene–Eocene transition, compressional stresses relaxed in the Alpine foreland, whereas collisional interaction of the Pyrenees with their foreland persisted. In the Alps, major Eocene north-directed lithospheric shortening was followed by mid-Eocene slab- and thrust-loaded subsidence of the Dauphinois and Helvetic shelves. During the late Eocene, north-directed compressional intraplate stresses originating in the Alpine and Pyrenean collision zones built up and activated ECRIS.At the Eocene–Oligocene transition, the subducted Central Alpine slab was detached, whereas the West-Alpine slab remained attached to the lithosphere. Subsequently, the Alpine orogenic wedge converged northwestward with its foreland. The Oligocene main rifting phase of ECRIS was controlled by north-directed compressional stresses originating in the Pyrenean and Alpine collision zones.Following early Miocene termination of crustal shortening in the Pyrenees and opening of the oceanic Provençal Basin, the evolution of ECRIS was exclusively controlled by west- and northwest-directed compressional stresses emanating from the Alps during imbrication of their external massifs. Whereas the grabens of the Massif Central and the Rhône Valley became inactive during the early Miocene, the Rhine Rift System remained active until the present. Lithospheric folding controlled mid-Miocene and Pliocene uplift of the Vosges-Black Forest Arch. Progressive uplift of the Rhenish Massif and Massif Central is mainly attributed to plume-related thermal thinning of the mantle-lithosphere.ECRIS evolved by passive rifting in response to the build-up of Pyrenean and Alpine collision-related compressional intraplate stresses. Mantle-plume-type upwelling of the asthenosphere caused thermal weakening of the foreland lithosphere, rendering it prone to deformation.     

岩溶地区现代土壤与洞穴石笋中单甲基支链烷烃与烷基环己烷对比研究

利用GC-MS（气相色谱—质谱仪）,对采自湖北清江流域和尚洞洞顶的土壤样品与洞内石笋样品进行分析,发现土壤中存在的七个系列单甲基支链烷烃在所有的石笋样品中均可以找到,呈现相似的分布模式,石笋中七个系列支链烷烃有可能来自洞穴滴水携带的土壤中的支链烷烃,但是也不能排除石笋原地生长的微生物的贡献。烷基环己烷的分布在土壤与石笋中呈现了相似的分布模式,但是主峰碳数有所变化,高碳数部分与低碳数部分的相对含量也发生了变化。主要原因可能是微生物选择性降解的结果,也有可能是土壤与石笋中微生物种类分布差异所造成的。本次研究初步显示了相对封闭稳定的洞穴沉积物与上覆土壤层中生物标志化合物的异同。      

Lower Carboniferous (Dinantian) stratigraphy and structure of the Walterstown-Kentstown area,Co. Meath,Ireland

Stratigraphic units are defined and described for the Lower Carboniferous succession in the Walterstown-Kentstown area of Co. Meath, Ireland. A complete (unexposed) Courceyan succession from the terrestrial red bed facies of the Baronstown Formation to the Moathill Formation of the Navan Group has been penetrated in several boreholes. Although the lower part of the sequence is comparable with the Courceyan succession at Navan and Slane, the middle part of the sequence differs markedly in the Walterstown-Kentstown area and two new members, the Proudstown and Walterstown Members, are defined in the upper part of the Meath Formation. Syndepositional faulting was initiated during the Courceyan, probably in latest Pseudopolygnathus multistriatus or early Polygnathus mehli latus time. Movement on the ENE trending St. Patrick's Well Fault influenced the deposition of the Walterstown Member and the overlying Moathill Formation and was probably associated with the development of the East Midlands depocentre to the south of the area. A second episode of tectonism in the latest Courceyan or early Chadian resulted in uplift and erosion and the development of ‘block and basin’ sedimentation. Subsequent transgression of the uplifted block led to the establishment of the Kentstown Platform, bounded to the north, west and south by rocks of basinal facies. The Milverton Group (Chadian-Asbian), confined to this platform, unconformably overlies Courceyan or Lower Palaeozoic strata and is subdivided into three formations: Crufty Formation (late Chadian), Holmpatrick Formation (late Chadian-Arundian) and Mullaghfin Formation (late Arundian-Asbian). The Walterstown Fault controlled the western margin of the Kentstown Platform at this time. Contemporaneous basinal sediments of the Fingal Group (Lucan and Naul Formations) accumulated to the west of the Walterstown Fault and are much thicker than age-equivalent platform facies. Platform sedimentation ceased in latest Asbian to early Brigantian time with tectonically induced collapse and drowning of the platform; platform carbonates of the Mullaghfin Formation are onlapped northwards by coarse proximal basinal facies of the Loughshinny Formation. A distinct gravity anomaly in the Kentstown area suggests the presence of a granitoid body within the basement. The Kentstown Platform is therefore considered to have formed on a buoyant, granite-cored, footwall high analogous to the Askrigg and Alston Blocks of northern England.     

Viscous effects on penetrating shafts in clays

The penetration of rigid objects such as piles and penetrometers into soils creates a zone of soil disturbance around them. The extent of this disturbed zone influences the resistance of the moving rigid body. This paper presents a theoretical framework to analyze the resistance in the disturbed zone created by a shaft penetrating a clay soil. The soil is modeled as a viscous material after it reaches failure [critical state (CS)]. The results of this analysis show that the viscous drag stress component on the shaft surface is influenced by the size of disturbed zone that has reached CS around the shaft, the shear viscosity of the soil and the velocity profile (or strain rate) in the CS zone around the shaft. The size of CS zone, the velocity profile and the viscosity of soil are interdependent. Large variation in viscous drag occurs when the size of the CS soil zone is less than four times the shaft’s radius. Limiting drag occurs when the size of the CS soil zone exceeds six times the shaft’s radius. The theoretical velocity distribution of the movement of soil in the CS zone shows that the soil is dragged along with shaft in the near field (close to the shaft surface) and moves upwards in the far field.     

Apport de la modélisation géophysique pour la compréhension de la structuration du pas de Calais

This study is based on an analysis of seismic, gravimetric and magnetic data to model the structure of the Dover Straits area. The Dover Straits are set in a transitional position within the Brabant para-autochthon, which lies between the Ardennes allochthon to the south and the Brabant Massif to the north. The seismic profiles show that this area is characterised by several superimposed Mesozoic basins, whose evolution has been controlled by the reactivation of Lower Palaeozoic faults. In common with the adjacent Weald–Wessex and southern North Sea basins, the Dover Straits area records a Jurassic extensional phase and a post-Cretaceous tectonic inversion. The geophysical modelling reveals the presence of a basement to these Mesozoic basins that exhibits Ordovician to Silurian structures, which cannot be detected on the seismic reflection profiles. In contrast to earlier interpretations, the modelling presented here suggests that the Brabant Massif continues southward beyond the Dover Straits and under the Brabant para-autochthon. Gravity data also provides evidence for the presence of granitic body at depth, in the vicinity of Km 27 on the seismic profile, which may have driven the uplift of the Silurian rocks in the area of the Straits. Similar granitic intrusions have been proposed to explain gravity anomalies along the Rhenohercynian Margin in Belgium, eastern and southern England. The geophysical modelling demonstrates the continuity of the basement and Mesozoic basin structures across the Dover Straits, suggesting a common geological evolution of the adjacent southern England–northern France regions. To cite this article: B. Minguely et al., C. R. Geoscience 337 (2005).     

Recharging of contaminated aquifer with reclaimed sewage water

About 40% of the water supply of Cairo, Egypt, is drawn from a groundwater reservoir located southeast of the Nile Delta. Several thousand shallow wells supply drinking water to the farmers from the same groundwater reservoir, which is recharged by seepage from Ismailia canal, the irrigation canal network, and other wastewater lagoons in the same areas. Sewage water lagoons were located at the high ground of the area, recharging contaminated water into the aquifer. Since the groundwater in this area is used for drinking purposes, it was decided to treat the sewage water recharging the aquifer for health reasons. In this paper a solution to the problem is presented using an injection well recharging good quality water into the aquifer. A pumping well located at a distance downstream is used to pump the contaminated water out of the aquifer. A three-dimensional solute transport model was developed to study the concentration distribution with remediation time in the contaminated zone.     

The spatial distribution and source of arsenic, copper, tin and zinc within the surface sediments of the Fal Estuary, Cornwall, UK

ABSTRACT Estuarine sediments commonly form major sinks for contaminants released during industrial activity. Many industrial processes lead to the release of metals initially in solution, which can then be adsorbed on to, for example, Fe hydroxides or clay minerals. However, in the mining industry, there are two major contaminant waste streams: (1) metals discharged in solution via mine drainage; and (2) particulate grains of the ore‐forming or related minerals released after ore processing. The release of particulate waste can have a major long‐term impact on environmental geochemistry. In this study, we have mapped the distribution of arsenic, copper, tin and zinc within the surficial sediments of the Fal Estuary, Cornwall, UK, an area that drains a historically important polymetallic mining district. There are clear spatial variations in the contaminants, with the highest levels (> 2800 p.p.m. As, > 5000 p.p.m. Cu, > 3000 p.p.m. Sn and > 6000 p.p.m. Zn) within Restronguet Creek on the western side of the estuary. Mineralogical studies show that small (< 20 µm) grains of detrital arsenopyrite, chalcopyrite, cassiterite and sphalerite are very abundant within the surface sediments. Most of the sulphide grains are fractured, but mineralogically unaltered, although some grains show alteration rims caused by oxidation of the sulphides. The geochemistry and mineralogy are indicative of sediment supply from the discharge of particulate waste into the estuary during historical mining activity. Subsequently, this particulate waste has been largely physically and biologically reworked within the surface sediments. Although considerable effort has been made to minimize contaminants released via mine drainage into the estuary, the potential flux of contaminants present within the intertidal and subtidal sediments has not been addressed. Benthic invertebrates living within the area have adapted to be metal tolerant, and it is likely that the dominant source of bioavailable metals is a result of alteration of the particulate mine waste present within the intertidal and subtidal sediments.     

牙形刺Idiognathodus swadei-Ⅰ.turbatus演化谱系在华南的发现及其意义

经国际莫斯科阶-卡西莫夫阶界线工作组2008年的投票表决,目前全球卡西莫夫阶的底界比传统底界提高了一个多亚阶;牙形刺Idiognathodus sagittalis和Idiognathodus turbatus是两个候选的底界标志种。牙形刺Id-iognathodus swadei-Ⅰ.turbatus演化谱系在华南连续的深水海相碳酸盐沉积剖面---贵州罗甸纳庆剖面的发现表明,Idiognathodus turbatus的首现是全球卡西莫夫阶底界的潜在标志;纳庆剖面作为目前最具潜力的候选层型剖面,值得进一步深入研究。