新型光纤光栅压力传感器承压面厚度对比研究

光纤布拉格光栅(FBG)传感器最常用的封装材料是环氧树脂粘合剂,容易老化和失效,会影响传感器的性能和寿命。该文采用一种新型光纤光栅压力传感器,比较厚度分别为2.0 mm、3.0 mm、3.5mm及4.0 mm的6061 T6铝合金承压面对新型光纤光栅压力传感器标定的影响。由试验结果可知,新型光纤光栅土压力传感器承压面厚度为2.0 mm的标定结果最差,拟合线性度为0.991 94,传感器重复性较差;承压面厚度为3.5 mm的标定结果最好,拟合线性度为0.999 77,重复性最好且传感器灵敏度误差较小。该研究结果可以为后续新型光纤光栅压力传感器的生产设计提供参考。

用承压面成像方法分析连杆螺栓拉伸问题

紧固件的承压面,反映出紧固件被拧紧过程的运动情况和受力情况,对连杆组件的连杆盖承压面用成像方法进行分析,发现主要原因是连杆盖尺寸超差,导致螺栓轴向力过大,进而发生螺栓拉伸故障。

采用瓦斯治理巷治理工作面承压区瓦斯

针对1175综采承压区段瓦斯涌出量大,瓦斯平凡超限,并且出现突出情况,介绍1175综采面过承压区施工瓦斯治理巷的布置及效果。

立井壁座的受力特征对宽度计算的影响

壁座是建井工程中重要的一部分,起到承托井筒质量,防止井壁破裂的作用,但是目前国家规范和设计手册中关于壁座宽度计算的规定不相同,对适用的地质条件也没有详细说明,本文基于壁座-井筒-基岩间的相互作用,建立了三者相互作用的受力平衡方程,根据壁座承压面法向应力必须小于岩体容许应力的强度条件,推导出壁座宽度计算公式,能够更为全面地反映壁座在井筒与基岩共同作用下的受力特征,及最终对壁座宽度计算的影响。

一种新型破碎锤──液压锤

随着公路的不断建设，在施工中对破碎工具的应用种类也越来越多。由于科技的发展，我国已生产出具有国际水平的一种新型破碎锤——液压锤。该产品居国内领先地位，是一种液压能转换为机械冲击能的破碎机具。可用于冶金、矿山、公路、铁路、建筑、市政工程等行业对岩石、混...

对影响混凝土质量评定因素的研究

本文通过对影响混凝土质量评定的的各种因素的分析,提出了检测过程中应注意的一些问题和对策,以提高检验结果的准确性。

新型水力自动闸门的研究设计

本文对一种新型水力自动闸门一前浮箱水力自动闸门的工作原理及设计要点进行了论述。并介绍了该闸门的国内外现有研究成果，可为工程技术人员对该种闸门的推广设计提供有价值的参考。

The Analysis of Seismic Data Structure and Oil and Gas Prediction

In this paper, a new concept called numerical structure of seismic data is introduced and the difference between numerical structure and numerical value of seismic data is explained. Our study shows that the numerical seismic structure is closely related to oil and gas-bearing reservoir, so it is very useful for a geologist or a geophysicist to precisely interpret the oil-bearing layers from the seismic data. This technology can be applied to any exploration or production stage. The new method has been tested on a series of exploratory or development wells and proved to be reliable in China. Hydrocarbon-detection with this new method for 39 exploration wells on 25 structures indi- cates a success ratio of over 80 percent. The new method of hydrocarbon prediction can be applied for: (1) depositional environment of reservoirs with marine fades, delta, or non-marine fades (including fluvial facies, lacustrine fades); (2) sedimentary rocks of reservoirs that are non-marine clastic rocks and carbonate rock; and (3) burial depths range from 300 m to 7000 m, and the minimum thickness of these reservoirs is over 8 m (main frequency is about 50 Hz).

Viscosity profile prediction of a heavy crude oil during lifting in two deep artesian wells

It has been known that the productivity of artesian wells is strongly dependent on the rheological properties of crude oils. This work targets two deep artesian wells(>5000 m) that are producing heavy crude oil. The impacts of well conditions including temperature, pressure and shear rate, on the crude oil rheology were comprehensively investigated and correlated using several empirical rheological models. The experimental data indicate that this heavy oil is very sensitive to temperature as result of microstructure change caused by hydrogen bonding. The rheological behavior of the heavy oil is also significantly impacted by the imposed pressure, i.e., the viscosity flow activation energy(Eμ) gently increases with the increasing pressure. The viscosity–shear rate data are well fitted to the power law model at low temperature. However, due to the transition of fluid feature at high temperature(Newtonian fluid), the measured viscosity was found to slightly deviate from the fitting data. Combining the evaluated correlations, the viscosity profile of the heavy crude oil in these two deep artesian wells as a function of well depth was predicted using the oilfield producing data.

Safe retaining pressures for pressurized tunnel face using nonlinear failure criterion and reliability theory

Based on the active failure mechanism and passive failure mechanism for a pressurized tunnel face, the analytical solutions of the minimum collapse pressure and maximum blowout pressure that could maintain the stability of pressurized tunnel faces were deduced using limit analysis in conjunction with nonlinear failure criterion under the condition of pore water pressure. Due to the objective existence of the parameter randomness of soil, the statistical properties of random variables were determined by the maximum entropy principle, and the Monte Carlo method was employed to calculate the failure probability of a pressurized tunnel. The results show that the randomness of soil parameters exerts great influence on the stability of a pressurized tunnel, which indicates that the research should be done on the topic of determination of statistical distribution for geotechnical parameters and the level of variability. For the failure probability of a pressurized tunnel under multiple failure modes, the corresponding safe retaining pressures and optimal range of safe retaining pressures are calculated by introducing allowable failure probability and minimum allowable failure probability. The results can provide practical use in the pressurized tunnel engineering.

Contact pressure distribution and support angle optimization of kiln tyre

According to the shearing force character and the deformation coordination condition of shell at the station of supports, the mathematical models to calculate contact angle and contact pressure distribution between tyre and shell were set up, the formulae of bending moment and bending stress of tyre were obtained. Taking the maximum of tyre fatigue life as the optimal objective, the optimization model of tyre support angle was built. The computational results show that when tyre support angle is 30°, tyre life is far less than that when tyre support angle is optimal, which is 35.6°, and it is unsuitable to stipulate tyre support angle to be 30° in traditional design. The larger the load, the less the nominal stress amplitude increment of tyre, the more favorable the tyre fatigue life when tyre support angle is optimal.

Characteristics of deformation and stress distribution of small coa pillars under leading abutment pressure

Based on the engineering project on a small coal pillar of 12,521 working face roadway in Xieqiao Coalmine, data regarding surface displacements of the coal pillar, deep displacements and mining stress have been collected and analyzed. The results show that macroscopic transverse fractures of the inner coal pillar are developed within 2–4 m of the roadway surface, which is located outside the coal pillar anchorage zone. There is a displacement of 530 mm at the monitoring point in the 6 m deep zone of the pillar. Transfer of the fracture zone is found in a small coal pillar and the fractures within 3–4 m of the coal-rock zone from the roadway surface undergo propagation and closure of cracks which means this fracture zone is transferred from 3–4 m outside the roadway to only 2–3 m from the roadway surface. In the monitoring zone, vertical and horizontal stresses increase with a feature that shows that acceleration in the deep zone of the pillar is greater than that in the shallow zone. Furthermore, the acceleration of vertical stress is also greater than that of horizontal stress with a peak value in the 4 m zone.The research findings provide a reference for the regulation of a reasonable width of coal pillar in coalmines and optimal control design of surrounding rock.

Characteristics of supersonic flow in new type externally pressurized spherical air bearings

In order to predict accurately the characteristics of supersonic flow in new type externally pressurized spherical air bearings under large bearing clearance and high air supply pressure, which could decrease their load carrying capacity and stability, a CFD-based analysis was introduced to solve the three-dimensional turbulent complete compressible air flow governing equations. The realizable κ-ε model was used as a turbulent closure illustrate that the interaction exists between shock waves The supersonic flow field near air inlets was analyzed. The flow structures and boundary layer, and the flow separation is formed at the lower comer and the lower wall around the point of a maximum velocity. The numerical results show that the conversion from supersonic flow to subsonic flow in spherical air bearing occurs through a shock region （pseudo-shock）, and the viscous boundary layer results in the flow separation and reverse flow near the shock. The calculation results basically agree with the corresponding experimental data.

Numerical Simulation of Land Subsidence at Tanggu District in Tianjin, China

Based on observed data from Tanggu District in Tianjin, a back-propagation neural network (BPNN) model was introduced to predict possible land subsidence due to exploitation of groundwater. According to model estimation under various hypothetical extraction scenarios, patterns of land subsidence at Tanggu District were studied and discussed.The predicted average background land subsidence rate of Tanggu is 9.47 mm/a.The significance of contribution of aquifers to land subsidence descends in order of units Ⅳ,Ⅲ,Ⅴ,Ⅱ.Land subsidence tends to deteriorate with the increase in total extraction rate.

Distribution pattern of front abutment pressure of fully-mechanized working face of soft coal isolated island

The front abutment pressure of a fully-mechanized workface of 11061 soft coal isolated island of Liangbei Coal Mine was measured and studied using a self-developed mining-induced stress monitoring system associated with electromagnetic radiation technology, and the effects of abutment pressure distribution on strata behavior we discussed. The results indicate that the miningdnduced influencing distance advanced at the fully-mechanized working face of soft coal isolated island is larger than that at the gen- eral working face at the isolated island, besides the fracture zone in front of working face was widened to some extent, and the influencing range caused by relaxations on both roadways became bigger with the advancing working face. Moreover, it can be indicated that mining has significant effect on strata behav- ior of fully-mechanized working face of soft coal isolated island, which is mostly distributed in the area of stress concentration. The research results have an important reference value for revealing the distribution pattern of the front abutment pressure of a fully-mechanized working face of soft coal isolated island, and controlling the coal-rock dynamic disaster occurrence under similar mining conditions.

Analysis on distribution law of the abutment pressure of the integrated coal beside the road-in packing for gob-side entry retaining in fully-mechanized caving face

The three-dimensional damage constitutive relationship of coal is established and distribution law of the abutment pressure of the integrated coal beside the road-in packing for gob-side entry retaining in fully-mechanized caving face under the effect of given deformation of the main roof is analyzed by the damage mechanics theory. And the relationship between distribution of the abutment pressure and thickness of coal seam is explored. The presented result is of great theoretical significance and practical value to the study on stability control of the surrounding rock of road-in packing for gob-side entry retaining in fully-mechanized caving face.

Influences of anisotropy and inhomogeneity on supporting pressure of tunnel face with kinematical approach

Based on the active failure mechanism generated by a spatial discretization technique, the stability of tunnel face was studied. With the help of the spatial discretization technique, not only the anisotropy and inhomogeneity of the cohesion but also the inhomogeneity of the internal friction angle was taken into account in the analysis of the supporting forces. From the perspective of upper bound theorem, the upper bound solutions of supporting pressure were derived. The influence of the anisotropy and heterogeneity on the supporting forces as well as the failure mechanisms was discussed. The results show that the spatial discretization characteristics of cohesion and internal frictional angle impose a significant effect on the supporting pressure, which indicates that above factors should be considered in the actual engineering.

Distribution laws of abutment pressure around fully mechanized top-coal caving face by in-situ measurement

In order to obtain the distribution rules of abutment pressure around the 1151 （3） fully mechanized top-coal caving （FMTC） face of Xieqiao Colliery, the KSE-II-1 type bore-hole stress gauges were installed in the tailentry and headentry to measure the mining-induced stress. The distribution rules of the front and side abutment pressure were demonstrated. The results show that distribution rules of stress are obviously different in the vicinity of the face and entries. The peak value of abutment pressure in the protective coal pillar and face are located commonly in front of the working face along the strike, and they are located at the stress-decreased zone near the face. There is no stress peak value in the lateral coal mass beside the headentry in front of the face on the strike, and the peak value of abutment pressure appears at the rear area of the face. There are stress peak values both in the protective coal pillar and in the lateral coal mass beside the headentry to the dip.

新型钢筋锚固板构造对比及锚固性能试验研究

张靖皋长江大桥南航道桥锚碇基础地下连续墙刚性接头钢筋采用了锚固板构造,在带肋双孔锚固板构造基础上,提出了一种简化的双孔锚固钢板,为了研究带肋双孔锚固板、双孔锚固钢板、单孔锚固板在混凝土中的锚固性能,以及双孔锚固钢板厚度的影响,共进行了6组钢筋锚固板拉拔试验,分析了不同锚固板拉拔试件的破坏模型、极限承载力、钢筋拉拔应力~加载端位移曲线、锚固段钢筋黏结应力与锚固板承压力间的分配。结果表明:所有拉拔试件基本都发生沿混凝土剪切裂缝造成的劈裂破坏,带肋双孔锚固板、双孔锚固钢板两种双孔锚固板类型的锚固性能相差不大,双孔锚固钢板的锚固性能受锚固板厚度的影响较小,其主要受锚固板承压面尺寸的影响。

夹板式单层玻璃板承载性能的简化设计方法

夹板式幕墙系统是一种新兴的玻璃幕墙体系,且近年来工程实践发展迅速,但其理论与设计方法的研究却远滞后于它的实际应用,尤其是目前的规范尚未对夹板式玻璃板承载性能的设计方法做出规定。本文在试验和大量有限元参数分析工作的基础上,提出了夹板式单层玻璃板面外受弯、面内局部承压以及压弯共同作用的受力性能简化设计方法,通过设计方法与试验结果的对比,进一步论证了简化设计方法的有效性。