深部软岩巷道扩修加固综合治理技术

分析了影响巷道支护效果的主要因素,针对影响因素采取"锚、喷、注"为主要支护方式,对深部软岩巷道扩修采取了"扩修一次支护"、"顶板注浆加固"、"全锚索二次加强支护"、"顶帮底全断面二次注浆加固"、"底板水治理"的治理措施,获得了良好的效果。     

巷道围岩强度弱化规律及其动态加固技术

本文结合巷道围岩强度弱化规律，首次提出软岩巷道的动态支护原理和分步加固技术，同时给出了一个喷锚注动态加固的成功实践，为软岩支护提供了新的方法。     

影响巷道的因素与不同的锚杆支护方法

影响巷道的因素主要有同岩强度、地应力、断面形状与尺寸，不同地质条件下锚杆支护的主要方法是松软同岩巷道锚注加固、复合顶煤巷锚带网加锚索联合支护、综合顺槽采用锚杆锚索联合支护、综放面未来锚网支护。     

深部高应力软岩巷道锚注支护施工技术研究

在对深部高应力软岩巷道变形破坏特征、变形形态和变形破坏的影响因素分析的基础上,概括了锚注支护施工工艺,将其成功地运用于深部高应力软岩煤、岩巷道,并对锚注施工提出了明确的技术要求。     

锚注技术在软岩巷道加固中的应用

某矿西主运输大巷围岩主要为泥岩，岩性较软，巷道在使用过程中变形严重，本文针对巷道变形原因，对巷道采取了锚注的支护体系，详细介绍了西主运输大巷锚注加固设计方案，对锚注加固参数进行了详细的论述，较好的控制了巷道围岩变形，取得良好支护效果。     

全断面锚注联合加固技术在软岩巷道中的应用

燕家河煤矿回风下山由于受围岩蠕变特性、动压等因素影响，巷道出现了较大变形甚至破坏。在分析回风下山变形特征的基础上，采用全断面锚注联合加固技术对回风下山破坏较严重段进行了修复加固，有效控制围岩变形与破坏。     

锚网索喷与注浆联合支护技术在深部软岩巷道中的应用

随着矿井开采深度的增加,矿山压力的加大,受力环境复杂,尤其是在大断面、软岩中的巷道施工,传统的支护理论和支护方式不能满足施工的要求,以前巷道支护通常采用锚网索喷或架棚支护,经过一段时间后,经常会出现巷道围岩来压,造成碹体脱落,开裂、底鼓等巷道塑性变形现象,影响正常使用,修复时即危险还影响煤炭的正常生产,通过采用锚网喷与注浆联合支护,实现了“锚注一体化”,确保了支护强度及施工安全,满足生产的需要。     

锚网喷注支护技术在深部软岩层巷道施工中的应用

深部软岩巷道具有较大变形特征,单一的支护方式难以控制。锚网喷支护与注浆加固围岩是一种共同作用的耦合主动支护方式．可以改变围岩力学参数,提高围岩强度。本文结合兴山煤矿施工三水平南一石门29层-30层总回风道的工程实践,分析了注浆加固围岩的工程特点,经工程应用表明,注浆加固技术显著提高了围岩的强度和承载能力,有效地控制了深部软岩巷道变形问题．是一种有效控制深部软岩巷道变形的支护形式。     

全封闭锚注支护在高应力软岩巷道中的应用

通过对唐山矿业公司12号井-793水平进、出车线围岩状况的分析,采用全封闭锚注支护马蹄形巷道,巷道的持续变形和底鼓得到有效控制,探索了解决软岩巷道修复周期短的方法。     

杨柳矿北翼高应力软岩架棚巷道修复研究

杨柳矿北翼主要开拓大巷，地处高地应力软岩条件，在架棚支护失效后，改用架喷注锚修复方案，即高性能超高强锚杆＋结构补强技术＋拱形支架的帮部锁腿梁结构，施工工艺为：清理破碎围岩-加网撤棚-喷浆-注浆-全断面长锚杆（索）主动控制围岩一底板长锚索锚注加固，取得了良好的效果，极大减小了复修的经济负担。     

火灾下型钢混凝土梁力学性能的研究

采用纤维模型法和有限元软件ABAQUS计算了火灾下型钢混凝土梁的变形以及耐火极限,初步了解了型钢混凝土梁的高温力学性能。在此基础上,利用纤维模型法分析了截面尺寸、截面含钢率、受拉钢筋配筋率、型钢屈服强度、钢筋屈服强度、混凝土强度、截面高宽比和钢筋的混凝土保护层厚度等参数对火灾下构件承载力的影响规律,最后提出了型钢混凝土梁耐火极限的实用计算公式。     

拱坝横缝钢筋与混凝土相互作用研究

本文在总结了钢筋与混凝土相互作用研究现状的基础上，建议了一个计算钢筋滑移量、钢筋粘结受力段长度的数值模型，该模型考虑了混凝土保护层厚度、截面混凝土应力分布的影响，并引用有关试验结果进行验证。文末在假定截面应力分布型态和临界混凝土保护层厚度条件下，将模型用于计算小湾拱坝横缝钢筋的滑移量、钢筋临界应力、钢筋受力段长度，计算结果表明用横缝钢筋控制横缝开度的这一工程措施基本可行，且建议的保护层厚度、横缝钢筋布置等均有一定工程参考价值。     

钢筋砼十字形柱的耐火极限研究

利用数值模拟程序RCSSCF分析了荷载比、柱计算长度、截面尺寸、荷载偏心率、配筋率和荷载角等参数对ISO834标准升温作用下钢筋砼等肢十字形柱耐火极限的影响规律。针对不同荷载比、柱计算长度、截面尺寸、荷载偏心率和配筋率共1080种工况进行了四周受火时钢筋砼等肢十字形柱的高温反应分析。在此基础上,定量给出了该类构件耐火极限的实用计算方法。研究表明:荷载角对十字形柱耐火极限影响较小;严格控制荷载比是提高十字形柱耐火极限的有效措施。     

压弯剪作用下钢筋混凝土柱荷载-变形分析

为研究不同破坏模式下钢筋混凝土柱的受力机理及性能,该文提出能够考虑压弯剪相互作用的钢筋混凝土柱荷载-变形分析模型。以修正压力场理论及传统纤维截面分析法为基础,将柱受力过程分为弯曲控制及剪切控制两个阶段,分别对控制截面受拉区和受压区进行分析,同时考虑了纵筋受压屈曲及P-Δ效应的影响,进而得到柱水平受剪承载力及其变形。最后,为验证模型的有效性,对所收集的拟静力试验柱进行了模拟。结果表明,压弯剪作用下钢筋混凝柱会表现出弯曲、弯剪及剪切三种不同的破坏模式,其荷载-变形性能差异较大,采用该文所提模型所得计算曲线与试验结果吻合较好,该模型能够被用于钢筋混凝土柱抗震性能分析。     

CFRP筋体外加固铁路预应力混凝土简支梁桥设计及试验研究

采用自主研发的CFRP筋体外预应力加固桥梁锚具装置(包括锚固装置和张拉装置),对铁路预应力混凝土简支梁桥进行加固设计和现场试验。针对CFRP筋体外预应力加固特点,计算预应力损失和CFRP筋配筋面积,验算加固桥梁的反拱、正截面强度、抗裂性、抗剪性以及挠度等;在此基础上,对大秦铁路线某16m预应力混凝土简支梁桥进行了现场加固试验。结果表明:该文提出的加固方法适用于实际铁路桥梁加固,加固后符合现行铁路相关规范和混凝土结构加固设计规范要求,且桥梁的受力性能得到明显改善。     

钢-混凝土双面组合梁受拉钢筋有效分布宽度

负弯矩区桥面板中受拉钢筋的应力分布存在滞后现象。考虑"拉应力沿桥面板厚度方向变化",结合有限元法,研究受拉钢筋有效分布宽度的计算问题。对29根双面组合梁进行了非线性有限元分析,研究了中支点附近负弯矩区桥面板中受拉钢筋的有效分布宽度在加载全过程中的变化;对弹塑性阶段有效分布宽度的主要影响因素进行参数分析,提出了塑性阶段有效分布宽度的简化计算方法。     

Optimal reinforcement of RC columns for biaxial bending

The Reinforcement Sizing Diagram (RSD) approach to determining optimal reinforcement for reinforced concrete beam and column sections subjected to uniaxial bending is extended to the case of biaxial bending. Conventional constraints on the distribution of longitudinal reinforcement are relaxed, leading to an infinite number of reinforcement solutions, from which the optimal solution and a corresponding quasi-optimal pragmatic is determined. First, all possibilities of reinforcement arrangements are considered for a biaxial loading, including symmetric and non-symmetric configurations, subject to the constraint that the reinforcement is located in a single layer near the circumference of the section. This theoretical approach establishes the context for obtaining pragmatic distributions of reinforcement that are more suitable for construction, in which distributions having double symmetry are considered. This contrasts with conventional approaches for the design of column reinforcement, in which a predetermined distribution of longitudinal reinforcement is assumed, even though such a distribution generally is non-optimal in any given design. Column and wall sections that are subjected to uniaxial or biaxial loading may be designed using this method. The solutions are displayed using a biaxial RSD and can be obtained with relatively simple algorithms implemented in widely accessible software programs such as Mathematica^® and Excel^®. Several examples illustrate the method and the savings in reinforcement that can be obtained relative to conventional solutions.     

Development of ductile composite reinforcement bars for concrete structures

In order to overcome the deficiencies of current composite reinforcement bars such as low elastic moduli, low pre-rupture elongation, brittle fracture as well as high cost, a new core-shell model of hybrid composite reinforcement bar has been developed in this study. In this model, steel and glass fibers are randomly dispersed across the cross section of the core while Twaron and carbon fibers are placed within the shell to improve the elastic modulus as well as to serve as a shield for protecting the glass fibers from alkaline attack; and the steel fibers from moisture and chloride induced corrosion. Glass composite reinforcement bars and hybrid composite reinforcement bars were fabricated by hand winding method. The tensile modulus and strength of the new hybrid reinforcement bars were determined to be 142 GPa and 628 MPa, respectively. New hybrid reinforcement bars were also conditioned in different alkaline environments and were evaluated for their alkaline resistance properties. Compared with glass composite reinforcement bars, the new hybrid composite reinforcement bars possess characteristics of alkaline resistance, good ductility and increased modulus of elasticity, while the material costs of such hybrid composite reinforcement bars are slightly higher than the glass composite reinforcement bars.     

Analytical study of beams strengthened by adhesively bonded reinforcement with variable properties using state space method

This paper uses the state space method to present an analytical solution for beams that are strengthened by externally bonded reinforcement with variable cross-sectional properties. The external reinforcement can be any elastic material, such as fiber-reinforced polymer (FRP) or steel (before yielding), and the variation of the cross-sectional properties of the externally bonded material can be stepped or continuous. Specific interest is directed to the interfacial shear stress and tensile stress of the externally bonded reinforcement, which are important to debonding analyses and the evaluation of strengthening effectiveness but were previously investigated only for externally bonded materials with uniform properties along the span. Solutions for beams under both concentrated and distributed loads are obtained, considering multiple spring supports. Numerical results are presented to evaluate the method and to investigate the interfacial stresses of beams externally bonded by FRP with different types of cross-sections. These results confirm the experimental observations that a tapered section can significantly reduce interfacial shear stress.     

新的k_(h0)-法计算单筋梁

介绍一新的钢筋混凝土单筋梁的配筋计算方法和算例,该法在混凝土受压区采用矩形加抛物线的应力分布,在计算中求解的未知量是混凝土边缘压应变或受拉钢筋应变,而不是"等效矩形应力"法中的受压区高度。该法是欧洲规范Eurocode2中采用的方法,计算过程简便,求得配筋后,无须在验算受压区高度;此外,还可用于弯压或弯拉构件的配筋计算。计算结果中除了含有计算钢筋面积的钢筋系数外,还有混凝土受压区边缘应变、受拉钢筋应变、受压区高度及内力臂系数等,结果一目了然。