Numerical simulation of the effect of coupling support of bolt-mesh-anchor in deep tunnel

The mechanical effects of bolt-mesh-anchor coupling support in deep tunnels were studied by using a numerical method, based on deep tunnel coupling supporting techniques and non-linear deformation mechanical theory of rock mass at great depths.It is shown that the potential of a rigid bolt support can be efficiently activated through the coupling effect between a bolt-net support and the surrounding rock.It is found that the accumulated plastic energy in the surrounding rock can be sufficiently transformed by the coupling effect of a bolt-mesh-tray support.The strength of the surrounding rock mass can be mobilized to control the deforma-tion of the surrounding rock by a pre-stress and time-space effect of the anchor support.The high stress transformation effect can be realized by the mechanical coupling effect of the bolt-mesh-anchor support, whereby the force of the support and deformation of the surrounding rock tends to become uniform, leading to a sustained stability of the tunnel.

Influences of surface and flexoelectric polarization on the effective anchoring energy in nematic liquid crystal

The physical effects on surface and flexoelectric polarization in a weak anchoring nematic liquid crystal cell are investigated systematically. We derive the analytic expressions of two effective anchoring energies for lower and upper substrates respectively as well as their effective anchoring strengths and corresponding tilt angles of effective easy direction.All of these quantities are relevant to the magnitudes of both two polarizations and the applied voltage U. Based on these expressions, the variations of effective anchoring strength and the tilt angle with the applied voltage are calculated for the fixed values of two polarizations. For an original weak anchoring hybrid aligned nematic cell, it may be equivalent to a planar cell for a small value of U and has a threshold voltage. The variation of reduced threshold voltage with reduced surface polarization strength is also calculated. The role of surface polarization is important without the adsorptive ions considered.

ANCHORING EFFECT ANALYSIS OF TENSIONED BOLTS

The paper analyses quantitatively the anchoring effect of tensioned bolts on surrounding rock strength, and defines two concepts: one is the surrounding rock strength increased amount Δτ13 and the other is the strength influence factor k. The anchoring effect of tensioned bolts is considered to increase a strength increased amount Δτ13 where Δτ13 is the product k and ten-sioned load p, i. e. Δτ13 = kp, where k is a function of two variables x and y. The distribu-tive properties both Δτ13 and k are also discussed in the paper, obtaining some useful results for designing bolting support parameters.

Mathematical Statistics Method of Evaluating Application Effects of a New Type of Gas Anchor

Based on the basic formula of the confidence interval and the sampling error of mathematical statistics, the mathematical statistics method of evaluating application effects of a new type of gas anchor was given in this paper. By the method mentioned above, the confidence interval and the sampling errors of the relevant mean value differences of Daqing Oilfield S block’s 150 wells, according to the mean value differences of the liquid producing capacity per day, the oil production per day, the submergence depth of the 10 sampling test wells, in which before and after a new type of gas anchor were laid down, were calculated. The calculation results show that a new type of gas anchor has a better effect of increasing oil production of oil well and enhancing pump efficiency. Through the real value differences analysis of the liquid producing capacity per day, the oil production per day, the submergence depth of 150 wells mentioned above, in which before and after a new type of gas anchor were laid down, it was verified. By using the confidence interval and the sampling errors of the liquid producing capacity per day, the oil production per day, the submergence depth mentioned above, in which before and after a new type of gas anchor were laid down, the application effects of a new type of gas anchor could be evaluated. And a mathematical statistics method of evaluation application effects of a new type of gas anchor is presented.

Study on the Influence of Radial Pressurization on Anchoring Performance of Bolts

Supporting soft rock roadways in coal mines has long posed a formidable challenge. Addressing issues such as the formation of soft rock strata, poor fracture development, limited tolerance, and the frequent and severe damage sustained by conventional bolts due to their low elongation and bearing capacity, this study employs bottom expansion and filling technology. It combines theoretical analysis with booster bolt pull-out tests to scrutinize the radial stress distribution of bolts under extrusion forces. Moreover, it conducts a comparative analysis of bolt bearing characteristics under varying radial pressurization conditions, delving into the impact of radial directional increases in compressive stress on bolt anchoring performance.

Synergistic effect of a new wedge-bond-type anchor for CFRP tendons

In order to improve the anchoring force of anchors for carbon fiber reinforced polymer(CFRP) tendons further, a new wedge-bond-type anchor for CFRP tendons was developed. The increment in anchoring force induced by the clamping segment of anchor was studied. Taking the deformation of all parts in clamping segment in the transverse direction into consideration, the calculation formula for the increment of anchoring force was proposed based on the linear elastic hypotheses. The proposed model is verified by experiments and conclusions are drawn that the anchoring force is influenced mainly by the inclination angle of clamping pieces, the length of clamping part and the thickness of bonding medium. Especially, the thickness of bonding medium should be lowered in design to improve the synergistic effect of anchors.

侵害品种权法定赔偿数额的司法决策因素检视及因应

品种创新是种业振兴的关键,识别侵害品种权法定赔偿的司法决策因素,以提高品种权司法保护水平,进而激励育种创新,实有必要。以2002-2023年侵害品种权适用法定赔偿的案例为样本,分析其时空特征,建立多元回归模型,探究法定赔偿数额的参考因素与影响因素。结果表明:侵害品种权法定赔偿适用“泛化”且判赔额较低,提高法定赔偿上限的立法举措效果甚微;法定赔偿参考因素缺乏量化标准,维权合理开支定位不清;锚定效应、审判经验等因素对司法决策影响显著。为提高品种权司法保护质效,建议采取如下措施:通过严格适用法定赔偿,消除举证责任障碍,降低证明标准,以克服法定赔偿“泛化”适用;通过确立赔偿数额计算标准和规则,另行计赔维权合理开支,以避免裁判的主观性;通过提高司法决策信息质量,提升法官素养,提供司法决策空间,以减少锚定效应,保证裁判的公平性。

地缘政治风险与人民币货币锚效应——基于“一带一路”合作国家和地区的实证分析

防范化解地缘政治风险,保持人民币币值的相对稳定,对稳慎推进人民币国际化具有重大意义。通过分析2015年8月至2022年7月“一带一路”合作国家和地区56种货币的汇率月频数据,探究了不同区域的货币锚定人民币的程度,并进一步基于Frankel经典货币锚模型测度了地缘政治风险对人民币货币锚效应的影响。实证结果表明:第一,美元虽仍是大部分地区的锚定货币,但人民币已逐步成长为东欧、东南欧、东南亚和东亚地区钉住的货币锚。第二,地缘政治风险能够显著影响人民币在部分地区的货币锚效应,但是在不同区域和不同贸易开放度的情况下具有显著的异质性。当地缘政治风险上升时,东欧和东南欧地区会更多地锚定人民币以规避汇率风险,而东南亚和东亚地区却会选择降低锚定人民币的权重以寻求汇率稳定;高贸易开放度的国家会更多地锚定人民币,低贸易开放度的国家更可能会减少锚定人民币。研究结果为稳慎推进人民币国际化和精准实施人民币国际化的国别策略提供了参考依据。

托顶煤巷道锚固“梁-拱”结构分类及顶板冲击失稳机制

我国煤矿托顶煤巷道冲击地压频发,且冲击动载下顶板灾害尤为严重。为探究托顶煤巷道顶板锚固结构类型和冲击失稳机制,以陕西某矿301工作面回风巷道大面积冲击垮顶为工程背景,运用相似实验、理论分析及数据统计等方法,分析了托顶煤巷道围岩应力、位移和巷表加速度的动载响应特征,研究了顶煤厚度与支护构件影响下顶板锚固结构的分类特征,探究了弹性波下托顶煤巷道的应力响应机制,提出顶板锚固“梁-拱”结构的冲击失稳机制,评估了301工作面回风巷道的抗冲能力,并提出了相应的抗冲支护优化方案。结果表明:①冲击动载下托顶煤围岩应力和位移等监测数据验证了顶板存在内、外层的梁或拱形锚固结构,因顶煤厚度增加,顶板内层锚固结构存在由“梁”向“拱”的转换;②基于顶煤厚度与支护构件相对关系,将顶板锚固结构划分为薄顶煤的“叠加梁-拱”、厚顶煤的“组合梁-拱”和特厚顶煤的“组合拱”,建立了厚煤梁由“梁”向“拱”转化的临界厚度指标;③顶板锚固梁结构和锚固拱结构的冲击失稳机制为动静载荷下分别达到其拉伸、剪切强度极限后破坏,锚固“梁-拱”结构对冲击载荷的放大效应受其尺寸影响明显;④特厚顶煤的“组合拱”结构中内层拱承载强度较低,可增加锚杆长度提升内层拱厚,对应的“组合拱”结构的承载能力上升明显,与抗冲能力评估结果相符。

四筋植筋混凝土结构偏心拉拔性能试验研究

为了研究多筋植筋混凝土结构的偏心拉拔性能,以偏心距、植筋间距为参数,设计2个四筋植筋混凝土结构轴心拉拔试验和5个四筋植筋混凝土结构偏心拉拔试验,分析偏心距、植筋间距对四筋植筋混凝土结构拉拔受力性能的影响。试验结果表明,所有四筋植筋混凝土结构试件均发生复合破坏。当其他条件相同时,随着偏心距增大,四筋植筋混凝土结构拉拔承载力减小。另外,在试验研究基础上,考虑偏心距、植筋间距、植筋边距、植筋深度的影响,建立了四筋植筋偏心拉拔承载力的计算模型和计算公式,计算值与试验值吻合良好,为四筋植筋混凝土结构的设计计算提供了技术依据。

人民币对“一带一路”沿线国家锚效应的实证研究

文章基于修正的二阶段Frankel-Wei模型,在其第二阶段回归分析中构建时变参数状态空间模型,对人民币及其他主要世界货币对“一带一路”沿线国家的货币锚效应进行样本期的分段动态检验、对比分析。根据检验结果,从中国自身和中国同沿线国家关系两个层面遴选指标变量,并构建二阶段Heckman模型研究人民币对“一带一路”沿线国家整体及“一带”沿线和“一路”沿线两个区域货币锚效应的影响因素。研究结果显示:人民币对沿线国家的货币锚效应已超过英镑,和日元基本相当,但和美元、欧元之间尚有较大的差距;目前,人民币对“一路”沿线的锚效应整体高于“一带”沿线国家;虽然人民币对沿线国家的锚效应水平不高且并不稳定,但在“一带一路”倡议提出并实施以来,其产生显著锚效应的沿线国家数量有较多的增加;且在沿线国家中,产生显著锚效应的区域也已逐渐形成。人民币对“一带一路”沿线货币锚效应影响因素的检验结果显示:无论是“一带一路”沿线整体还是“一带”沿线及“一路”沿线两个区域,在是否选择锚定人民币及已锚定人民币的国家中,人民币锚效应大小的影响因素均存在一定的差异。据此,文章进一步探讨未来该如何进一步提升人民币对沿线国家的货币锚效应。

金属预埋吊件的拉拔力学性能试验研究

为研究金属预埋吊件(简称预埋吊件)的拉拔力学性能和破坏机制,考虑无边距和有边距效应的影响,研发了一套拉拔加载装置,设计并完成了预埋吊件混凝土试件的拉拔试验。其中无边距影响的预埋吊件混凝土试件采用了5种预埋吊件,有边距影响的预埋吊件混凝土试件采用了3种预埋吊件,并运用ABAQUS模拟无边距影响的试件拉拔试验进行验证。结果表明:无边距影响的预埋吊件中销栓型预埋套筒、锚杆型内螺纹套筒以及锚筋型内螺纹套筒发生了预埋吊件拉断破坏,双头预埋吊杆试件发生了劈裂破坏,锚板型预埋套筒发生了理想的混凝土锥体破坏;有边距影响的混凝土预埋吊件均发生混凝土锥体破坏。

用户感性偏好导向的智能语音交互设计评价方法

用户感性偏好是智能语音交互设计的重要依据,为解决评价过程中存在的用户实际决策行为与其感性评价结果不一致的问题,提出了一种用户感性偏好导向的直觉模糊锚定评价方法。首先,采用直觉模糊集表征用户对智能语音交互设计的感性偏好信息,以充分描述用户偏好的模糊性与不确定性。其次,将最优最劣思想融入序数优先级方法以确定权重,在保证运算过程简便性的同时,克服了该方法在排序方面存在的缺陷。再次,从数理角度刻画了锚定效应在评价过程中的作用机制,并将锚定效应融入智能语音交互设计评价方法,就其对最终评价结果的影响进行量化分析。最后,以某智能车载系统语音交互设计为例,验证该方法有助于提高预测用户实际决策结果的准确性和可信度。

路基高边坡自适应锚索支护效果及稳定性研究

该研究以贵州毕威高速公路乌木铺高边坡支护为工程背景,采用大型有限差分软件FLAC^(3D)进行数值模拟,分析支护结构在各阶段的受力机理和工作性能,研究表明,在安装锚索之前,安全系数为1.06;在安装1 400 kN和1 500 kN锚索之后,安全系数增加到1.11;安装所有锚索后,安全系数增加到1.29,在锚索的锚固作用下,边坡的滑动趋势变小,边坡水平和竖向位移明显减小,边坡分级支护后的自适应锚索的锚固效果较好,边坡基本稳定。验证自适应锚索分级支护方法在乌木铺高边坡的适用性和可行性,为准确确定边坡的真实应力状态提供理论依据和数值参考。

深基坑新型张拉嵌入复合排水型锚固结构支护特性数值仿真分析

传统锚固结构很难满足软土地区深基坑工程工期紧、支护效果要求高的需求,对此提出张拉嵌入复合排水型锚固结构。通过分析新型支护结构的锚固机制得出:在基坑开挖过程中锚杆受力分为预张拉、端阻力递增和锚固作用失效3个阶段;给出了新型锚杆承载力计算方法;采用有限元软件模拟分析了新型结构的支护效果和排水特性。结果表明:新型锚杆轴力分布与普通锚杆不同,在预张拉锚头位置轴力出现陡增;相比于普通锚杆,新型锚固结构支护效果更好,能够使坡面最大水平位移减小37.2%,更有利于基坑稳定;新型锚固支护结构具有较好的排水效果,能够快速消散临空坡面附近的孔隙水压力。

考虑锚胫作用下拖曳锚在成层土中的嵌入机制

深水系泊系统及其系泊基础的开发已成为发展清洁能源“海上风电”项目的关键课题。拖曳锚由于其较大的承载力和易安装等诸多优势而具有较好的发展前景。基于极限塑性上限分析法,建立了考虑锚胫作用的拖曳锚在成层土中的嵌入轨迹、姿态以及承载力预测模型。利用已有模型试验对本模型进行验证,结果表明:考虑锚胫作用模型轨迹预测误差控制在13.5%,轨迹和角度预测误差相比于未考虑锚胫作用的模型分别降低了78.32%和36.9%。硬土层的强度、厚度和深度共同制约着拖曳锚的嵌入能力。首先,强度比影响最明显,强度比越大,嵌入深度越小,直至无法穿透硬土层;其次,是深度影响,深度越大,承载力越大。能够穿透硬土层的条件下深度对轨迹和角度影响不明显,不能够穿透硬土层条件下深度越大,嵌入深度越大,最终角度越小;最后,是厚度影响,硬土层厚度越大,嵌入过程中承载力越大。

回采巷道锚杆索支护优化设计与应用

针对山西长平煤矿2302工作面掘巷完成后,回采时采动压力剧增,巷道锚杆支护不能满足安全开采要求的问题,从岩体内部构造与岩层压力传递角度分析了巷道变形失稳机理,以巷道顶板和帮部变形失稳特点剖析了巷道变形破坏特征,通过锚杆锚索的岩体改性性质阐明了锚杆锚索作用机理。结合实际地质情况,对2302工作面回采巷道锚网索支护进行优化设计,通过FLAC^(3D)数值模拟软件计算对比分析了巷道支护方案优化前后的顶板垂直位移与岩体塑性破坏区范围,确定了支护方案优化后的支护效果更佳。现场工业性试验与巷道实时垂直位移监测得出优化后的支护方案巷道垂直方向变形量最大82 mm,最小49 mm,巷道支护方案优化效果良好,具有很好的可行性。

应变法在摩阻试验中的应用与研究

预应力孔道的成孔质量和锚下有效预应力是预应力施工技术的重难点。为掌握孔道弯曲半径和关键点定位坐标准确性,以及预应力施工张拉质量,采用应变法对摩阻试验和反拉法的各试验参数进行验证和对比分析。研究成果可为预应力施工张拉质量的控制提供参考。

Effect of Surface Texture on Tensile Shear Strength of 1060Al-PET Welding Joints

Joining metal to plastic can lighten weight of products to reduce energy consumption.However,it is difficult to achieve high-strength welding between metal and plastic.To address this problem,the methods of surface texture pretreatment and laser irradiation welding was proposed to achieve the high-strength connection of metal and plastic.In this study,with different parameters of laser power and texture morphology,1060 Al with surface texture treatment was joined to polyethylene terephthalate(PET)by laser irradiation welding from metal side.Study showed that as the laser power increased,the tensile shear strength of joints increased first,and decreased thereafter.Tensile shear tests demonstrated that the mechanical force of joint was strengthened contributed to mechanical anchorage formed by surface texture.The depth-width ratio of the texture grooves affected the tensile shear process of the joint.According to the result of temperature simulation,the existence of texture grooves reduced the heat transfer efficiency,and the heat dissipation at interface was also impeded in course of laser welding.Finally,the maximum tensile strength of 1060Al-PET joint reached 48.4 MPa,which was close to the strength of PET matrix.The bonding mechanism of the 1060Al-PET joints was composed of mechanical bonding and chemical bonding.This study proposes an effective method to join metal to plastic which achieved high-strength connection between metal and plastic.

复合坚硬顶板巷道切顶卸压围岩控制技术研究

以肥城白庄煤矿9807运输顺槽为研究对象,通过现场勘测,分析了复合坚硬顶板巷道围岩的变形特征,并根据复合坚硬顶板巷道控制原则,提出了可优化巷道围岩应力环境、抑制锚固结构破坏的“长锚索+深孔预裂爆破”协同控制技术。现场实践结果表明,采用该协同控制技术后,巷道顶板最大沉降量为34 mm,两帮最大收敛量为59 mm,实现了对复合坚硬顶板巷道围岩的有效控制。