More broadly, the mining-induced ground pressure disasters result from numerous contributing factors. In addition, the mutually independent multi-source parameters exhibit complicated intrinsic correlations. Nonetheless, the false-positive rates of ground pressure disasters of conventional single-parameter forecasting tend to be excessively higher, significantly hindering their widespread application. In this study, the support numerical models of mining-induced rock roadways in nine categories of three-centered arch cross-sections in metal mines were created, and the substantial computer simulation was carried out under the condition of reciprocally various rock mass quality and roadway support parameters. Moreover, the extensive simulation results of rock roadway support optimization design covering adequate information were quantitatively analyzed. Furthermore, the underlying association laws between the integral stability safety factor and the information entropy of the system chaos representation parameter were revealed during the instability evolution process of mining-induced rock roadways. Meanwhile, the presented time-varying characteristics of the entropy value of surrounding rock system were deduced. Consequently, the summarized research achievements can provide pivotal theoretical support for multi-scale stability evaluation of complex ore-rock geological mass, and prediction and early warning of ground pressure catastrophes integrating multi-source information.

For several decades, the disadvantages of traditional metallic rock and soil support structures have become increasingly prominent. As a result, it is urgent to seek lightweight, high-strength, durable and green economic substitute products made from the basalt fibre reinforced composites. Combining the two-phase material summing principle of composite material mechanics and the extension and application of Mohr–Coulomb strength criterion, the uniaxial tensile computing model of a cylindrical polymer specimen containing randomly distributed and discontinuous basalt fibres was established in accordance with the numerical simulation software Flac3D. Furthermore, the influence laws and intrinsic mechanism of the number of discrete fibres and different fibre distribution angles on the integral axial tensile properties of a cylindrical specimen with chopped basalt fibre thermosetting resin matrix composites were investigated and elucidated, and the stress–strain curve of basalt fibre thermosetting resin matrix composites were obtained. Consequently, the results have indicated that: i) the axial tensile strength of the polymer system can be enhanced through the incorporation of a moderate quantity of chopped fibres, with the resultant improvement typically not surpassing a 10% increment; ii) when the number of fibres has increased to the quantitative state, namely, the fibre density reaches 1.02 pieces/cm3 or more, the amplification of axial tensile strength of composite material will be controlled; iii) the fibre distribution directions, are maintaining a 0° parallel state to the axial direction of the specimen and the ones of load application, will ensure that the tensile strength of the composite can be sufficiently utilized. As the production process within the composite industry have become increasingly adept, the research results hold substantial value for further promoting the development, testing and optimizing application of various types of high-performance basalt fibre reinforced composite products.

位于绍兴市的新建轻纺城大桥为一大跨度系杆拱桥,主桥结构形式为(16+144+16)m下承式钢管混凝土系杆拱,桥宽41 m,吊杆布置采用可换式吊杆,全桥共设26对吊杆.大桥上跨古运河及古纤道等世界级文物保护单位,因此对桥梁新建过程中结构受力合理性及位移可控性的要求更为严格.利用数值模拟软件MIDAS Civil进行建模计算,配合全面的施工监控,保证整个施工过程安全可靠,同时研究该类系杆拱桥主要受力构件在各工况下应力和变形情况.结果表明,各工况下中内力及位移最大的主梁与拱肋,各实测数据值和理论计算值吻合较好,验证了大桥监测方案的科学性.研究结果对于指导该类桥梁的施工具有一定的参考价值.

The cofferdam method is generally applied in the construction of underwater pier foundation in bridge engineering, and the pouring of bottom sealing concrete is one of the important links in the construction of the cofferdam. The bottom sealing concrete can prevent water seepage and balance the main body of the cofferdam, and its structural size and construction quality have a great influence on the above functions. Under the condition of large water level difference, it is difficult to determine the reasonable thickness of the bottom sealing concrete. There are few related studies in this field, and there is a lack of systematic summary of calculation theory. This work theoretically deduces the approximate solution of ultimate bending moment and ultimate stress of the bottom sealing concrete, introduces two different calculation methods, systematically summarizes the calculation methods of three kinds of ultimate stress, analyzes the calculation methods of ultimate bonding force, and uses ANSYS finite element software to simulate a specific bottom sealing concrete model, and compares it with the theoretical calculation results. The maximum stress obtained by the approximate solution is closer to the actual monitoring data than the traditional method, and the calculation method of the bonding force can be used to make a rough estimate.

为了研究大跨度系杆拱桥拆除施工过程中拱肋和风撑关键控制截面的内力变化情况以及支架受力变化情况,同时为相同拱桥拆除工程提供指导,通过对一座大跨度系杆拱桥的主拱圈拆除过程进行数值模拟分析,运用桥梁数值分析软件Midas civil对各施工阶段的结构受力和变形情况进行了计算.结果表明施工过程中,拱肋和风撑的内力的变化情况以及支架受力情况均满足施工要求,从而验证了该大跨度系杆拱桥的拆除施工方案的可行性,同时得到了拱肋关键控制截面的位移变化具体数值,为施工过程中布置观测点进行变形监测提供了依据和参照.

It is still an issue to identify the vehicle weight for bridges with multi-T-girders which is essential in bridge operation management. In this study, a vehicle weight identification method is proposed for bridges with multi-T-girders. To consider the load transverse distribution effect, first the separation variable method is adopted to separate the spatial influence surface function of vehicle load into the product of two single-valued functions. Then the procedures of the vehicle weight identification method are proposed using the measured strain responses of the T-girders caused by the passing vehicle accordingly. A numerical example of a bridge with five T-girders and an experimental example of a bridge with two T-girders are conducted to verify the feasibility and effectiveness of the proposed method. Furthermore, the performance of the proposed method is compared with the typical existing method in which the load transverse distribution effect is not considered.

采用新型的胶凝材料来改性淤泥,在不降低含水率的情况下,通过新型胶凝材料的改性作用将大量的水分结合到晶体结构中,从而固化淤泥,制成淤泥建筑砌块,其具有较高的强度和耐水性,克服现有免烧砖的强度与耐水性差的缺点,既解决了淤泥的处理,又为建筑行业提供了材料.

Mode shape identification is a crucial task in the field of bridge health monitoring. This paper proposes a mass-normalized mode shape identification method for bridge structures on the basis of its essential property of bearing vehicle load. First, the relationship between the bridge frequencies changes due to a parking vehicle, and the amplitudes of the mass-normalized mode shapes at the parking point is established through theoretical derivation. Subsequently, the algorithm and procedures to extract the mode shapes by using the frequencies measured on a two-axle vehicle that parks at different locations of the bridge progressively are proposed. Then the determination of the two-axle parking vehicle parameters and the distinctive features of the proposed method are discussed. Numerical and experimental examples of different bridge types are conducted to investigate the feasibility and effectiveness of the proposed identification method. The results indicate that the proposed method can obtain high spatial resolution mass-normalized mode shapes accurately with only one sensor on the parking vehicle.

The duration of earthquake ground motions has insignificant effects on analysis results for performance-based seismic design of bridges (PBSD ).The incremental dynamic analysis of a six span reinforced concrete (RC ) continuous girder bridge was performed for decoupling the influence between duration,frequency spectrum and amplitude of structural seismic responses by using several groups of real and artificial earthquake waves matching the same target response spectrum and having different probability distributions with 5 -95%significant duration.The correlation between duration and seismic demanded of the RC girder bridge revealed that the mean,dispersion and probability distribution of duration of earthquake ground motions have little influence on displacement engineering demand parameters (EDP)but important effects on the probabilistic estimation (mean),dispersion and probability distribution of energy EDPs or fatigue failure and cumulative damage parameters;if energy EDPs are used in PBSD,the mean,dispersion and probability distribution of duration of earthquake ground motions must be in accordance with the real seismic hazard at the bridge site. An optimal method to rationally select real earthquake ground motions for PBSD based on the total probability theorem was presented,it could effectively consider the effects of mean,dispersion and probability distribution of duration on seismic demands of bridge structures and significantly improve the precision of analysis results and computation efficiency.

综述了非路面式桥梁动态称重（B-WIM）30多年来的发展历史,重点介绍了B-WIM新方法。从基本理论与算法、工程应用、产品研发等几个方面总结了非路面式桥梁动态称重研究取得的成就与结论,分析了现阶段B-WIM存在的主要问题,为B-WIM今后的研究与发展提供参考。结果表明:精确检测车轴信息,拓展B-WIM的适用桥型范围,发展二维B-WIM方法和提高测试结果精度将成为今后重要的研究方向。

The investigation along Qinghai-Tibetan Railway shows that the main reason for the de- struction of embankment is the thaw settlement.Besides,frost heaving and compressibility of the embankment fill must also be considered.By experiment the Beiluhe's typical soil sample,this pa- per studies the the physical properties and mechanical properties which are closely relation to the frost heaving and thaw settlement.

Most areas along the Qinghai-Tibet Railway are of perennial frozen soil.The top layer,which is unsteady,is easily affected by seasonal freezing and thawing.Physical property as well as other features,such as intensity and deformation of perennial frozen earth must be taken into accunt before the structure design of the roadbed made up of frozen soil.Therefore,many indoor soil tests are carried out,including the granule analysis test,the specific gravity of soil particle test,the compaction test of soil,the compression test and trixial compression test.