软土中打桩施工不良影响的防范问题研究

采用有限元数值模拟对减少软粘土中打桩挤土影响的施工措施进行了分析。数值模拟表明：采用预钻孔及设置隔离槽，可以有效控制打桩引起的地表水平位移及隆起。控制打桩流水对减小打桩影响的作用体现为已打入桩对土体竖向隆起的遮帘及打桩点远离被保护构筑物。此外，强调了信息化施工在防范打桩施工不良影响中的作用。     

建筑工程施工中沉桩工艺的具体应用实践

建筑工程的施工过程中,最关键是要保证建筑结构的稳定性。施工单位在实际施工中,为了提高建筑结构的稳定性,应高度重视沉桩工艺的应用。本文利用文献分析法和经验总结法,对多种不同的沉桩工艺进行了详细的分析,探讨了沉桩工艺在建筑工程施工中的具体应用要点,明确了有效应用沉桩工艺提高建筑工程的稳定性,不仅要做好打桩准备,准确把握打桩要点,做好打桩记录,还要做好打桩施工质量的控制与管理。     

房建钢筋混凝土预制桩施工分析

介绍了房建钢筋混凝土预制桩的施工准备工作,从打桩设备选取、打桩顺序、打桩施工三方面,阐述了房建钢筋混凝土预制桩的施工技术,指出预制桩可以提升地基的荷载能力,实现机械化操作。     

φ1500 mm特大口径钢管桩试验

通过对宝钢某工程φ1500mm钢管桩进行打桩试验、高应变动测试验、垂直静载荷试验，取得了重要的设计、施工参数，从而为合理选择桩尖持力层。确定试桩的极限承载力、合适的桩锤制定了相应的打桩工艺、技术标准。     

基于光纤传感技术的泥岩地基动力打入桩施工效应现场试验

为探讨泥岩地基动力打入桩的施工效应与承载力异常问题，基于低温敏光纤应变传感器联合桩端全截面轮辐压力传感器实时监测打桩过程中桩身应力及桩端阻力，明确打桩过程中试桩内力和桩端阻力随贯入深度的变化规律；通过竖向抗压静载荷试验与高应变动测分析各试桩的承载特性；利用打桩锤击数和锤重分析锤击能对动力打入桩沉桩效应的影响，借助打桩前后桩边标准贯入试验锤击数随桩长的分布，揭示动力打桩对桩周泥岩强度的影响机制。结果表明：沉桩过程中不同测试传感器得到的桩端阻力时程曲线变化规律较为一致，静载试验获得的试桩极限承载力比高应变动测得到的结果偏高，试桩均表现出端承型桩的特性；重锤打桩桩身应变变化幅度明显较大，打桩能量与试桩的竖向承载力有关，高能量打桩导致泥岩结构损伤加重，会降低动力打入桩的承载力；打桩后桩周泥岩的标贯试验锤击数与打桩前相比明显减小，宏观上表明动力打桩对桩周泥岩结构造成不同程度的损伤，可以认为泥岩结构损伤是动力打入桩承载力降低的主要原因之一。     

管桩沉桩过程模拟及监控

为确保预制管桩设计合理并提高施工质量,在对沉桩过程进行研究的基础上,介绍了模拟实际打桩过程时柴油锤的模型、重锤与桩冲击响应的数值模拟及模型实现的主要功能等,分析了打桩监控试验的目的意义。分析表明,在设计环节模拟实际打桩过程中桩-土-锤之间的相互作用,对选择的桩型和打桩系统进行可行性分析,初步确定设计方案,然后实施试打桩并进行打桩监控试验,验证和调整初步设计方案中的桩-土-锤参数,实现设计方案的优化是非常必要和可行的。     

锤击桩动应力作用下的有限元分析

本文利用有限元分析软件对打桩过程中桩身的动应力进行分析,直观显示了打桩过程中锤击荷载在桩身任意位置的传递过程,以及应力波的传播对桩身各个部位的影响,并针对不同情况采取相应的质量控制措施,弥补了在施工中只能靠经验控制打桩质量的不足,从而提高一次打桩成桩率,减少桩的浪费,降低工程成本,以供参考。     

双缸双作用液压打桩锤液压系统数值仿真

液压打桩锤利用液压能驱动锤体升降，其优点是可根据土质情况及桩材质的强度，合理选择冲击力，此外，液压打桩锤适合打斜桩作业以及水下桩基施工，同时不存在软土起动困难的问题，能适应各种气候下的施工作业。     

直径12m钢筋混凝土贮仓结构施工

本文介绍ф１２ｍ钢筋混凝土贮仓结构的桩工程采用免剥离法施工技术，从桩制作到打桩工艺进行了论述；同时，对承台、筒仓壁、漏斗和仓顶平台施工作了简述．     

联合检测法控制桩基质量的技术应用

本文根据工程实践，介绍了桩基施工前，根据地质勘察资料，用经验公式法（按土的物理性质指标查表法）估算钢筋混凝土预制桩单桩竖向承载力标准值、竖向承载力设计值。在打桩机型号确定后，用打桩公式法（动荷载试验法）试算该桩的单桩竖向容许承载力值、竖向极限承载力标准值、竖向承载力设计值和打桩经验贯入度。把以上估算、试算的单桩竖向承载力三项值和打桩经验贯入度作为控制打桩质量的初步指标。然后结合高应变动力检测法取得工程桩试桩的单桩竖向极限承载力标准值、竖向承载力标准值、竖向承载力设计值和最终贯入度。结果表明，以上三种单桩竖向承载力值均满足了设计要求的单桩竖向承载力设计值，从而确定用打桩最终贯入度为主。控制打桩质量。     

Development and applications of trenchless technology in China

Trenchless technology has developed for almost 10 years in China since the first symposium on trenchless technology was held in Beijing (Peking) in 1996 and the China Society for Trenchless Technology-CSTT was established in 1998. Driven by the dramatically increased demand for underground pipeline installation throughout the nation, China has made significant progress in research and development in trenchless technology in the past 10 years. For example, there are more than 200 contractors engaged in trenchless construction, using more than 2000 horizontal directional drilling machines, among which approximately 700 have been introduced in the last year, and the biggest HDD rig in the world is now in China. In addition, China has made many achievements in education, research, and new products development and has accomplished many challenging projects in terms of complexity, diameter and distance in this field. There is a huge market potential for trenchless technology in mainland China.This paper presents the latest research, education, training, marketing and technical status of trenchless technology in China, and discusses the potential market, trends and factors that will influence trenchless technology in the next decade in China.     

PCB and chlorinated pesticide concentrations in swine and bovine adipose tissue in Sweden 1991-1997: spatial and temporal trends

Results from the Swedish control programme regarding organochlorines in food were used to determine time trends of organochlorine concentrations in adipose tissues from swine (4-8 months old) and bovines (non-dairy, 12-36 months) slaughtered between 1991 and 1997. Moreover, possible regional differences in concentrations were studied, as well as differences in concentrations depending on sex and age of the slaughtered animals. Multiple linear regression indicated that the concentrations of PCB, p,p'-DDE, HCB and alpha-HCH decreased by 4-17% per year, suggesting that the decline in organochlorine concentrations in the Swedish environment and biota reported during the 1970s-1990s also has occurred in meat-producing animals during the 1990s. The concentrations of PCB, DDE and HCB in bovines and PCB and DDE in swine were 1.4-3.8-fold higher in the southern parts of Sweden than in the northern parts of the country, indicating a regional difference in exposure of the animals. The organochlorine concentrations were higher in bovines than in swine, and declined faster in swine than in bovines. Moreover, the concentrations of CB 153 and p,p'-DDE were similar in bovines, but in swine the average concentrations of the two compounds differed two-fold. Apart from possible species differences in metabolism of organochlorines, this may be due to differences in the age at slaughter between swine and bovines, and differences in husbandry of the animals. In the latter case, swine are generally kept inside during their whole life span, whereas bovines are kept outside grazing during the summer period. Finally, a sex-dependent difference in concentrations was indicated in swine, but not in bovines. Our study shows that a lot of information can be 'extracted' from control program results.     

Differences in Mn uptake and subcellular distribution in different barley genotypes as a response to Cd toxicity

A hydroponics experiment was carried out in greenhouse to study the genotypic differences in Mn uptake and subcellular distribution in response to Cd toxicity. Increased Cd level in medium caused a significant reduction in plant height and fresh weight, and ZAU3 and Wumaoliuling being the least and the most affected genotypes, respectively. There was a marked difference in proportion of Mn accumulation in different fractions relative to the total Mn amount in tissues among the 4 fractions, with the soluble fraction FIV showing the largest proportion in shoots, followed by organelle containing fraction (FIII), while cell wall (FI) and chloroplasts FII being the smallest. Meanwhile, Cd significantly increased FIII Mn accumulation proportion, but decreased FIV proportion, with significant genotypic difference of Wumaoliuling being the least increase in FIII and the greatest decrease in FIV among the 4 genotypes. In roots, the major pool of Mn content was FI, FIV, and FIII, and Cd induced no significant changes. Furthermore, Cd caused a significant reduction in subcellular Mn concentration of FI and FIV fractions in shoots and the 4 fractions in roots, with more pronounced in Cd-sensitive cultivar Wumaoliuling in root FII, FIII and FIV, and shoot FI, FII, and FIII, while little difference in both Mn concentrations of root FI, and shoot FIV.     

Mechanical behavior of different sedimentary rocks in the Brazilian test

Mechanical behavior of the rock in tensile stress environment remains an unresolved problem in the underground mining, where surrounding rocks commonly experience tensile failure. In the present study, tensile failure behavior of three types of sedimentary rocks is investigated experimentally and numerically. The deformation response, fracture propagation, and splitting pattern as well as energy conversion of the rocks are examined in the Brazilian test with a testing machine, high-speed camera, and image scanning system. The tested rocks tend to show elastic-brittle-plastic deformation behavior in the biaxial stress state. Tensile strengths of the coal, mudstone, and sandstone are 1.2, 3.9, and 13.4 MPa, respectively. The coal and mudstone split in a static mode while the sandstone in dynamic mode. The splitting fracture initiates at the disk center in the coal and sandstone, and it emerges at the loading point in the mudstone. The fracture propagates more quickly in the rock with larger strength. It uses 1200.0, 5.8, and 0.4 ms, to break out sample surface of the coal, mudstone, and sandstone, respectively. The joint roughness coefficient (JRC) of the splitting fracture is largest (20.1) in the mudstone, followed by that in the coal (17.7), and it is smallest in the sandstone (15.3). A continuous-discontinuous coupling model, which is capable of analyzing the stress distribution and fracture propagation synergistically, is developed and calibrated against the experimental data. The numerical model accurately reproduces mechanical behavior of the tested rocks observed in the Brazilian test. The splitting fracture propagates along the maximum tensile stress plane in the sandstone. The propagation direction is locally influenced by the grain boundary with small tensile strength in the coal while, in the mudstone, the fracture is mainly formed along the grain boundary. Such differences in the fracture propagation path lead to the increasing trend from the JRC of the splitting surface in the sandstone to that in the coal and finally to that in the mudstone.

     

Experimental copper and chromium deficiency and additional molybdenum supplementation in goats. II. Concentrations of trace and minor elements in liver, kidneys and ribs: haematology and clinical chemistry

Since the mid-1980s a previously undescribed disease has affected moose in south-western Sweden. Investigations made to reveal evidence of a viral aetiology have proved unsuccessful. Trace element studies in apparently healthy moose shot during regular hunting suggested a trace element imbalance, with excessive molybdenum uptake causing secondary copper deficiency. The results also indicated a possible chromium deficiency. To verify this hypothesis, an experimental study was performed in male goats fed a semi-synthetic diet for 1.5 years. The animals were kept and treated in four groups: Controls, Cu-deficient group (group 1), Cr-deficient group (group 2), and combined Cu- and Cr-deficient group with additional supplementation of tetrathiomolybdate for 10 weeks at the end of the study (group 3). The present paper presents tissue contents of trace and minor elements, haematology and clinical chemical parameters. Feed consumption and weight development, as well as pathological and histopathological investigations, were also performed in this study, but these results are presented elsewhere. Changes in trace element concentrations were determined by comparing groups 1, 2 and 3 with the control group. Increased concentrations were observed for Al, Ca, Co, Fe, Mo, Pb, Se in the liver; for Al, Cd, Co, Cr, Mo in the kidneys; and for Mn and Mo in the ribs. Considerable accumulation of Mn in ribs seems to be a useful way to determine oxidative stress. Decreases in Mg and P in all organs and blood serum is characteristic of Cu deficiency and molybdenosis. Also the ratio of Ca/Mg was increased as the result of tissue lesions causing an intracellular increase in Ca and decrease in Mg. The trace element changes observed in group 1 were enhanced by the Mo supplementation in group 3, resulting in characteristic patterns, 'spectra' of changes. The alterations were not as remarkable in group 2 as in the two other groups. However, Cr deficiency considerably influenced Al, Co, V and to a smaller extent also Mn in ribs. In groups 1 and 2, only a few minor changes were detected in the haematological parameters, probably caused by increased adrenal activity after transportation of the animals. In group 3, severe anaemia was present but also a leukopenia. For the different clinical chemical parameters measured, all three groups showed changes, explained mainly by the altered activity of enzymes induced by trace element deficiencies and imbalance. Impaired carbohydrate and lipid metabolism was seen in groups 1 and 3, with increased concentrations of glucose, lactate and triglycerides in serum. Increased concentrations of total bilirubin were measured in all three groups (bile stasis was also seen post mortem). A considerably increased concentration of serum urea was found in group 3, although there were no indications of renal insufficiency or dehydration. Regarding hormones, a substantial decrease was seen in thyroxine (T4) in group 3 as a result of the molybdenosis, but a minor decrease was also seen in group 1. Insulin on the other hand showed increased levels in group 3--and especially in group 2 due to the Cr deficiency but also affected by the molybdenosis. As could be expected, Cu deficiency (groups 1 and 3) caused low levels of caeruloplasmin, secondarily affecting the Fe metabolism in these animals. Protein abnormalities, detected as altered electrophoretic patterns of serum proteins, were also seen mainly in group 3. The findings were also confirmed by multivariate data analysis, where PCA revealed the overall impact of the deficiencies, and PLS regression coefficients indicated the influence on the various analytes.     

Heat and cold stresses in different climate zones across China: A comparison between the 20th and 21st centuries

Summer and winter discomfort in terms of heat and cold stresses in the nine major architectural climate zones and sub-zones across China in the 21st century were investigated using predictions from general circulation models for the low and medium emissions scenarios. For the six severe cold and cold climate zones in the north, reductions in cumulative cold stress outweighed the increase in cumulative heat stress resulting in an overall decreasing trend in the annual cumulative stress, and vice versa for the other three warmer climate zones in the south. Compared with the 20th century, significant reduction in the cumulative cold stress was observed across the six zones in severe cold and cold climates, ranging from 15.8 in cold-III to 42.3 in severe cold-II. There were modest increases in the cumulative heat stress from 0.3 in cold-II to 12.3 in cold-III. For the warmer climates in the south, reduction in cumulative cold stress ranged from 7.6 in hot summer and warm winter (HSWW) to 10.3 in hot summer and cold winter, while cumulative heat stress increased from 9.9 in the mild zone to 30.6 in HSWW. A reduction in cold stress would result in less winter heating and an increase in heat stress more cooling requirement.     

Accumulation of heavy metals in circumpolar willow ptarmigan (Lagopus l. lagopus) populations

A circumpolar survey of heavy metals in willow ptarmigan liver and kidney revealed considerable variations in Cd content in Canada and Scandinavia. The Cd content in central Canada was comparable with that in Scandinavia and Russia, at least for kidney. However, in both liver and kidney the median for Canada as a whole was much higher than in the other countries. Some Canadian locations had exceptionally high levels, several birds having >50 mg kg(-1) in liver and >400 mg kg(-1) in kidney. In Norway, the Cd content was highest in central mountain areas in south Norway and inland locations in the two northernmost counties. Five locations in central and north Norway showed mean Cd levels in kidney above 100 mg kg(-1). It is difficult to evaluate regional differences in Sweden, but most locations had the same Cd level as moderately contaminated locations in Norway. Cd levels in Russia were comparable to moderately contaminated locations in the other countries. Due to a high intake of willow, naturally rich in Cd, direct comparison of the Cd level in willow ptarmigan from different locations cannot reveal the effects of long-range pollution. The Pb concentration in willow ptarmigan kidney and liver varied significantly in Norway and Canada, but not in Sweden and Russia. Levels in Sweden and Russia were comparable to those in Canada and low levels in Norway. The highest median value from all locations within countries was found in Norway, both in liver and kidney. The highest Pb content was found in south Norway, indicating an effect of long-range pollution in willow ptarmigan. The level in western Canada was significantly higher than in central Canada. The Hg content in liver varied significantly from one location to another in all the countries and in kidney everywhere except Sweden. In Scandinavia, there is no distinct regional pattern. Canada had a significantly higher Hg level in central than western regions in both tissues the opposite of that found for Cd and Pb. Cu and Zn showed significant variations from one location to another in liver and kidney in Canada and Norway, but only in kidney in samples from Sweden. Comparison between western and central Canada revealed a significant difference for Cu in liver, samples from central Canada having more. There are no significant differences from one country to another, but some localities in Canada seem to have higher Cu concentrations in kidney than are found in Scandinavia and Russia.     

贵州晴隆大厂锑矿构造蚀变体元素地球化学特征

研究主要针对黔西南地区构造蚀变体(SBT)中大厂锑矿床的典型剖面,采集茅口组的茅口灰岩,龙潭组的碳质泥岩、粉砂岩、粘土岩,峨眉山玄武岩组凝灰岩、沉凝灰岩、碳质粘土岩和SBT中的强硅化灰岩、角砾状强硅化灰岩、硅质岩、凝灰岩及角砾状粘土岩组合,对岩石或矿石进行主量元素和微量元素分析,利用等离子质譜方法分析大厂地区构造蚀变体及其上覆地层和下伏地层各类岩石样品的稀土元素组成。表明热液蚀变作用强烈,成矿物质可能为深部成矿流体带入。     

江西省市级健康教育所卫生服务能力的综合评价

目的全面、客观地了解江西省市级健康教育所卫生服务能力水平,为卫生行政部门制定健康教育发展有关政策提供科学依据。方法采用普查方法。并对江西省8所市级健康教育所采用自制的调查问卷表进行调查;对各市级健康教育所卫生人力、房屋、设备装备、服务功能及收支情况等方面的相关数据先进行指标筛选,然后将指标指数化,计算分比。结合五类一级指标的经验权重系数,确定各指标权重,求得江西省8所市级健康教育所的加权秩和比,最后进行最佳分档归类。结果江西省8所市级健康教育所各指标综合指数最高的分别为南昌市X9、九江市和宜春市X7、上饶市X17、赣州市X13、萍乡市X1、新余市X20、鹰潭市X14。21项二级指标中X3指标得分最高,其分比值、权重系数也最高。秩次和加权秩和比结果显示：鹰潭市得分最高,RSRW为0.708;萍乡市得分最低,RSRW为0.311。归档结果显示：九江市和鹰潭市健康教育所卫生服务效果为优,南昌市、上饶市、宜春市、赣州市、新余市健康教育所卫生服务效果为良,萍乡市健康教育所卫生服务效果为差。结论运用加权秩和比法能够较为全面、科学地反映健康教育所卫生服务水平。     

中国绿道规划建设实践——从提级统筹到制度并轨

绿道在中国经过多年实践发展,在理论内涵、规划选线、综合效益等各方面都已有许多成果支撑.基于可公开获取的一系列文献资料,立足于绿道在中国各省市近20年的具体实践过程,梳理绿道在规划体系中的角色转变、在指标设置中的逐步细化和在管控上的落实方式,总结绿道实践在中国从提级统筹、常态认同到制度并轨3个阶段的发展变化,在展望绿道后...