基于地质雷达的透水砖铺装道路结构层厚检测方法试验研究

透水砖铺装道路是海绵城市建设中控制地面径流的重要技术手段,其各层构造厚度是道路质量评价的主要参考指标之一。针对钻芯取样法测厚效率低、代表性差,地质雷达测厚法多层构造测厚精度低等问题,开展了基于地质雷达的透水砖铺装道路结构层厚检测方法试验研究。通过钻芯反算法标定了透水砖铺装道路各结构层的相对介电常数,采用高频地质雷达开展了透水砖铺装道路现场测厚试验,实测雷达数据的处理结果能准确追踪出透水砖铺装道路各个层位分界面,精确算得各层位厚度。计算厚度与钻芯取样测厚平均差值为4.06mm,标准差为2.374mm。试验结果表明,基于高频地质雷达的透水砖铺装道路结构层厚检测方法能够实现透水砖铺装道路高精度多层结构测厚。

层厚误差对反算模量精度的影响研究

根据落锤式弯沉仪(FWD)弯沉数据反算模量,需输入结构层厚度作为已知量。由于施工时层厚变异性大,导致结构层厚度误差成为影响反算模量精度的重要因素。使用路面雷达量测弯沉测点处的实际结构层厚度,并将设计厚度与真实厚度分别代入模量反算软件,由不同的计算结果分析误差影响,得出一系列结论。

自密实夹芯保温剪力墙受剪分析及理论研究

通过对自密实混凝土夹芯复合剪力墙的抗剪试验研究其两侧不等厚混凝土的裂缝发展以及钢筋的应力应变曲线的变化规律,同时建立桁架+拱模型,推导自密实混凝土夹芯复合剪力墙的抗剪承载力计算公式,并与试验结果对比.结果表明,较厚侧混凝土承担主要受剪承载力,较厚侧混凝土钢筋应变发展缓慢,刚度较大;较薄侧混凝土只起保护层作用.推导出的受剪承载力计算公式的计算值同实验值的误差很小,适用于自密实混凝土夹芯复合剪力墙的抗剪承载力计算.

Arch structure effect of the coal gangue flow of the fully mechanized caving in special thick coal seam and its impact on the loss of top coal

Based on the characteristics of the top coal thickness of the fully mechanized caving in special thick coal seam,the long distance of coal gangue caving,as well as the different sizes of the coal gangue broken fragment dimension and spatial variation of drop flow,this paper uses laboratory dispersion simulation experiment and theoretical analysis to study the arch structure effect and its influence rule on the top coal loss in the process of coal gangue flow.Research shows that in the process of coal gangue flow,arch structure can be formed in three types:the lower arch structure,middle arch structure,and upper arch structure.Moreover,the arch structure has the characteristics of dynamic random arch,the formation probability of dynamic random arch with different layers is not the same,dynamic random arch caused the reduction of the top coal fluency;analyzing the dynamic random arch formation mechanism,influencing factors,and the conditions of instability;the formation probability of the lower arch structure is the highest,the whole coal arch and the coal gangue arch structure has the greatest impact on top coal loss.Therefore,to prevent or reduce the formation of lower whole coal arch structure,the lower coal gangue arch structure and the middle whole coal arch structure is the key to reduce the top coal loss.The research conclusion provides theoretical basis for the further improvement of the top coal recovery rate of the fully mechanized caving in extra thick coal seam.

POSITIVE INVERSION STRUCTURE OF THE CENTRAL STRUCTURE BELT IN TURPAN-HAMI BASIN

The central structure belt in Turpan-Hami basin is composed of the Huoyanshan structure and Qiketai structure formed in late Triassic-early Jurassic, and is characterized by extensional tectonics. The thickness of strata in the hanging wall of the growth fault is obviously larger than that in the footwall,and a deposition center was evolved in the Taibei sag where the hanging wall of the fault is located. In late Jurassic the collision between Lhasa block and Eurasia continent resulted in the transformation of the Turpan-Hami basin from an extensional structure into a compressional structure, and consequently in the tectonic inversion of the central structure belt of the Turpan-Hami basin from the extensional normal fault in the earlier stage to the compressive thrust fault in the later stage. The Tertiary collision between the Indian plate and the Eurasian plate occurred around 55Ma, and this Himalayan orogenic event has played a profound role in shaping the Tianshan area, only the effect of the collision to this area was delayed since it culminated here approximately in late Oligocene-early Miocene. The central structure belt was strongly deformed and thrusted above the ground as a result of this tectonic event.

Rational concrete cover of prestressed concrete beams and slabs for fire resistance

As the influence of the ratio of the characteristic value of structural resistance to that of frequent combination effect, K, on the thickness of concrete cover of prestressed concrete （PC） beams and slabs for fire resistance is not considered sufficiently in design criteria for concrete structures in China and other countries at present, numerical analyses were carried out by ANSYS software on unbonded prestressed concrete （UPC） oneway simply-supported and continuous slabs and beams, and bonded PC simply-supported and continuous beams subjected to fire in 186 cases. In the analysis, K, section dimensions and the thickness of concrete cover are regarded as independent variables and some calculation parameters determined by trial and error based on test resuits. Calculation formula for fire endurance of UPC simply-supported and continuous slabs was proposed, and the recommended thicknesses of cover of PC beams and slabs was presented in consideration of the influence of K and section dimensions as well as fire endurance requirements. Comparison analysis of relevant design criterions in China and other countries was performed to verify the rationale of the proposed values.

长江隧道沥青路面结构与材料功能一体化研究

以国家863项目"抗滑、阻燃、降噪多功能隧道路面结构设计与铺装技术"为依托,以武汉长江隧道工程为背景,研发了沥青路面材料AFNA,在其满足长江隧道路面的"抗滑、阻燃、降噪"使用要求的同时,应用结构与材料功能一体化的思想,通过分析路面面层厚度组合,得出最佳路面面层厚度和面层材料参数,并成功应用于武汉长江隧道。