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1.
为解决新疆红鄯(红山口—鄯善)高速公路沿线板块状盐渍土用于工程建设的问题,基于渗透试验、无侧限抗压强度试验、CBR试验和承载力试验,研究了板块状盐渍土的路用性能。结果发现:板块状盐渍土的天然抗压强度受含盐量分布不均匀、土样级配不同和试件尺寸效应等因素的影响,其值为2.8~28.6 Pa,相差极大;板块状盐渍土的CBR值高达120%,远大于非板块状盐渍土的CBR值(28.6%),其弯沉值远小于设计弯沉值。这些结果说明,在工程实际中控制水的浸入,就可以充分利用板块状盐渍土作为路基的地基;结合渗透性试验成果和新疆红鄯高速公路周边环境的气候条件与降雨特征,提出对现场粗粒、细粒板块状盐渍土区段盐溶的深度处理分别为80 cm和50 cm。  相似文献   

2.
考虑层厚的路面弯沉修正系数研究   总被引:2,自引:0,他引:2  
路表弯沉实测值与计算值之间常常存在较大偏差,需以弯沉综合修正系数调整.现行沥青路面设计规范中,弯沉综合修正系数F缺乏对路面结构层厚度的考虑,且存在“反常现象”,即随着土基模量的增大,设计厚度也增大的现象.通过现场试验路的测试分析,提出了新的F计算式,以反映F随不同路面结构层厚的变化规律,适应不同层厚的路面结构.  相似文献   

3.
阐述了荣乌线新河至辛庄子段高速公路大部分路段土质为粉砂性盐渍土,此类土同时具备了粉砂土和盐渍土的特性。用此种土填筑路基,路基表面极易破坏、松散、难以成型,且路基的整体强度较低,路基弯沉值达不到设计要求。本文通过用水泥固化剂和石灰固化剂分别对该土进行改性试验,并通过室内试验与现场试验相比较、改性前数据与改性后数据相比较,来确定科学合理的路基改良方案,从而使路基的各项检测指标均能满足设计要求。  相似文献   

4.
为了建立基于沥青路面动态参数设计方法的路面质量验收标准,对弯沉综合修正系数F进行了研究.利用ABAQUS有限元程序,引入土基的非线性本构模型及其他结构层的动态模量来计算路表理论弯沉.修筑室内足尺试验路,并利用FWD测试其弯沉,根据F的定义,计算试验路各结构的F值.分析<公路沥青路面设计规范>及已有研究成果中的F修正公式...  相似文献   

5.
硫酸盐渍土的融沉是造成地基二次破坏的主要原因。为了探究不同含盐量和含水率在单向升温条件下硫酸盐渍土的融沉规律,以宁夏地区硫酸盐渍土为研究对象开展室内融沉试验。结果表明:(1)硫酸盐渍土的融沉可根据环境温度的不同分为三个阶段:升温初期(-24℃~5℃),融沉率增长较缓;升温中期(5℃~20℃),融沉率增长速率显著;升温后期(20℃~24℃),在含盐量较低时融沉率趋于稳定,含盐量较高时增长幅度渐缓;(2)含水率低于最优含水率时,2%含盐量土体在升温中期融沉率达到最大,而含水率高于最优含水率时,5%含盐量土体在升温后期融沉率达到最大;(3)含盐量较低(<2%)时,最大融沉率随含盐量增大而增大;含盐量较高(>2%)时,融沉率因含水率的高低呈现两种不同的变化趋势:含水率小于最优含水率的土体最大融沉率开始下降并趋向于稳定,而大于最优含水率的土体最大融沉率继续缓慢增加;(4)建立的最大融沉率预测模型与试验值有较好的拟合效果,可用于硫酸盐渍土融沉率的预测和评价。  相似文献   

6.
聚苯乙烯泡沫板(EPS板)在国内外多年冻土区工程中的应用较为广泛,但对于在盐渍土中使用保温材料应用研究相对还比较少。为了研究随外界环境条件改变聚苯乙烯(EPS)盐渍土路基温度场变化特征,本文主要在新疆地区农二师21团-24团公路路段长期监测数据的基础上,运用ABAQUS有限元分析方法,对盐渍土EPS隔热路基的温度场进行数值模拟。通过对比分析,验证了模拟结果的准确性,研究了在硫酸盐渍土中EPS的保温效果;提出了保温板铺设的最佳位置及适宜厚度;总结分析了保温板铺设位置及厚度与路基填土高度的关系。  相似文献   

7.
胡捷 《科技信息》2011,(17):I0297-I0297,I0319
由于地质条件的差异不同地区的建筑环境也存在着相当大的差别,本文就新疆地区盐渍土对建筑的影响作了相关分析,根据氨离子、硫酸根离子等的破坏特性以及水分、温度和反复冻融等因素,研究钢筋混凝土的耐久性问题。  相似文献   

8.
聚苯乙烯泡沫板(EPS板)在国内外多年冻土区工程中的应用较为广泛,但对于在盐渍土中使用保温材料应用研究相对还比较少。为了研究随外界环境条件改变聚苯乙烯(EPS)盐渍土路基温度场变化特征,在新疆地区农二师21团-24团公路路段长期监测数据的基础上,运用ABAQUS有限元分析方法,对盐渍土EPS隔热路基的温度场进行数值模拟。通过对比分析,验证了模拟结果的准确性,研究了在硫酸盐渍土中EPS的保温效果;提出了保温板铺设的最佳位置及适宜厚度;总结分析了保温板铺设位置及厚度与路基填土高度的关系。  相似文献   

9.
亚氯盐渍土的融陷性广泛影响着新疆公路基础建设。为研究亚氯盐渍土的融陷特性,以冻融循环为前提,采用固结仪杠杆加压法,研究含水率、干密度和上覆轴压对罗布泊亚氯盐渍土融陷系数影响规律,试验结果表明:亚氯盐渍土融陷系数随冻融循环次数增加而增大,随含水率、上覆轴压增大而增大,随干密度增大而减小;亚氯盐渍土冻融循环5次后融陷系数趋于固定值2.53%,压力小于50KP时,融陷系数增长速率较快,压力大于50KP时,融陷系数增长速率逐渐减慢。研究成果可为分析亚氯盐渍土融陷机理和公路融陷病害防治提供参考。  相似文献   

10.
西宁地区盐渍土的特征及工程处理措施   总被引:1,自引:0,他引:1  
概述了西宁地区三级阶地以上盐渍土的分布。黄土状盐渍土湿陷、溶陷机理,通过测定(湿陷+溶陷)系数,利用差减法确定湿陷和溶陷所占的比例,分析对比后得知西宁地区南山段盐渍土湿陷性占主导地位;同时提出西宁地区盐渍土工程地基处理要以防治结合、综合治理的原则,并采取相应的防水、地基基础和结构措施。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

16.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

17.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

18.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

19.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

20.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

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