穿断层隧道NPR锚索支护体系抗震特性振动台试验研究

为研究具有负泊松比效应(negative Poisson’s ratio,NPR)的恒阻大变形锚索在地震作用下的吸能特性与动力响应规律,利用振动台开展含断层隧道使用普通锚索支护以及使用NPR锚索支护的振动台物理模型试验,对比分析地震作用下处于不同围岩条件中以及使用不同锚索进行支护时隧道结构的动力响应规律。研究结果表明:在同一地震波作用下,使用NPR锚索进行支护的隧道结构破坏程度与使用普通锚索进行支护的隧道结构相比有明显的改善,表明NPR锚索在地震作用下具有良好的吸能特性,能够为隧道结构提供有效支护;通过对比分析普通锚索与NPR锚索的锚索轴力时程曲线可知,在地震波作用下,普通锚索会发生破断现象,轴力突降至零,而NPR锚索的高恒阻力能够持续提供有效支护;分析隧道结构各测点的加速度、应变、土压力等动力响应可知,隧道断层区域在地震作用下的动力响应更为明显,隧道结构在地震作用下呈现出拱肩→拱腰→拱顶的破坏规律,这一研究成果为类似隧道工程的支护对策提供了理论参考。

降雨诱发滑坡的NPR锚索控制机理及临滑预警

为研究降雨滑坡的控制及临滑预警技术,以熊家山滑坡为原型,通过分析边坡变形的时空特征,设计了相似模型试验.以普通预应力锚索(简称PR锚索)和NPR锚索为加固材料,运用高速摄像机、孔压、土压和锚索力传感器,分析了降雨诱发的滑坡规律和锚索控制机理,并结合现场试验探究了滑坡牛顿力变化规律.结果表明:孔隙水压力突降与边坡局部滑塌近似同步;NPR锚索力突降,边坡内部产生局部变形;PR锚索因无法承受大变形被拉断失效,而NPR锚索凭借恒阻大变形特性产生高应力吸能控制功能,促使边坡达到二次平衡状态;NPR锚索在滑坡前表现出明显的“先突增,后突降”的变形-临滑动力学规律;现场试验揭示了滑坡全过程牛顿力演变规律,提前7.5 h发出临滑预警.

NPR锚索对白云岩矿失稳边坡控制效应研究

节理裂隙是露天矿开采中边坡失稳的主要影响因素,因此,研究节理裂隙有利于解决矿区边坡开采的安全性问题。以北京黄峪口白云岩矿失稳边坡为工程地质背景,采用现场调查(测线法和赤平极射投影法)、NPR锚索数值模拟和现场监测方法,以NPR锚索主动支护思想为核心对其进行了试验研究。研究表明:①黄峪口白云岩矿边坡岩层基本呈水平状或与边坡走向方向一致,边坡体结构破碎,节理裂隙发育,存在软弱夹层和多条滑带,边坡有严重失稳的趋势。②NPR锚索入射角为20°时达到边坡最佳支护效果,边坡位移约2.55 cm,说明NPR锚索对破碎边坡起到较大的抗滑作用。③根据现场监测得出NPR锚索的锚索轴力可达300 kN左右,支护后的边坡较稳定。研究反映出,NPR锚索对节理裂隙发育的边坡控制效果较好,可为类似露天矿边坡治理提供参考。

NPR锚索对跨断层软岩大变形隧道控制技术研究

为探究NPR锚索对东马场跨断层软岩大变形隧道控制效果,首先对NPR锚索进行静力拉伸试验,验证其恒阻大变形的能力和具有良好的抵御外力的效果;随后开展NPR锚索对东马场隧道围岩变形控制的三维物理模型试验。试验现象和数据表明:在开挖过程中,隧道围岩也没有出现较大垮落和坍塌,NPR锚索对软岩隧道围岩有较好的支护效果。在加载完成后,NPR锚索对非断层处的隧道围岩最大位移约为14 mm,断层处的围岩最大位移约为21 mm,隧道区域所受应力分布的不规律性,导致隧道围岩出现挤压变形,位移曲线呈振荡状。在NPR锚索的支护下,围岩应力最大发生在左拱肩,围岩临空面3 cm处切应力最大(0.3 MPa),隧道未出现大规模的不对称破坏现象,隧道总体呈现出“小塌而不垮”,变形总体可控。

软岩隧道NPR锚索主动控制关键技术

为解决横断山区软岩隧道的大变形问题,本文以云南省昌宁至保山高速公路昌宁隧道为工程背景,采用理论分析、现场试验等方法,从作用机理、支护方案、施工工艺等方面对软岩隧道开展了高预紧力恒阻大变形(NPR)锚索主动支护及关键技术研究。结果表明:被动支护下,隧道围岩节理裂隙发育、黏土矿物含量高、围岩强度低、微观结构存在细小溶蚀孔、结构疏松等是昌宁隧道围岩发生变形破坏的主因;提出了“NPR锚索+PR锚索+“W”钢带+高强柔性网”主动支护技术,并通过现场松动圈测试等试验,确定了NPR锚索、PR锚索等的支护参数;针对极破碎围岩及含水软岩的特殊环境,提出了“先喷后支+复喷”和“锚固端下缘封堵+钢绞线端头加丝”NPR锚索主动支护优化技术;现场试验结果表明,NPR锚索主动控制技术能够有效控制软岩隧道围岩大变形,最大变形量由原来的2125 mm控制到300 mm以内,保障了隧道支护结构的安全。

黄峪口白云岩边坡变形机理分析及NPR锚索支护效果研究

延庆黄峪口边坡具有丰富的白云岩资源,在降雨作用下出现了严重的失稳现象,边坡前缘及坡体表面出现了多条裂缝,目前,针对该边坡的失稳机理及支护对策缺乏精细剖析。本文通过现场调查、数值模拟实验的手段研究了强风化白云岩边坡的失稳机理,并通过现场监测的方法验证了NPR锚索对该类破碎岩质边坡的支护效果。研究结果显示:白云岩边坡坡体多为张性切裂缝和剪切裂缝,滑坡主要发生蠕滑变形,滑坡属于牵引式顺层岩质滑坡;降雨对边坡的影响主要是岩土体饱和孔压和非饱和孔压共同作用的结果,雨水过大会导致边坡前缘处基岩软化,造成滑坡的发生;矿区内边坡通过NPR锚索的加固后稳定性得到明显提升,牛顿力基本保持在300 kN以上,可以实现对边坡的稳定性控制和远程实时监测预警。

Instability mechanism of mining roadway passing through fault at different angles in kilometre-deep mine and control measures of roof cutting and NPR cables

The angle α between the fault strike and the axial direction of the roadway produces different damage characteristics. In this paper, the research methodology includes theoretical analyses, numerical simulations and field experiments in the context of the Daqiang coal mine located in Shenyang, China. The stability control countermeasure of "pre-splitting cutting roof + NPR anchor cable"(PSCR-NPR) is simultaneously proposed. According to the different deformation characteristics of the roadway, the faults are innovatively classified into three types, with α of type I being 0°-30°, α of type II being 30°-60°, and α of type III being 60°-90°. The full-cycle stress evolution paths during mining roadway traverses across different types of faults are investigated by numerical simulation. Different pinch angles α lead to high stress concentration areas at different locations in the surrounding rock. The non-uniform stress field formed in the shallow surrounding rock is an important reason for the instability of the roadway. The pre-cracked cut top shifted the high stress region to the deep rock mass and formed a low stress region in the shallow rock mass. The high prestressing NPR anchor cable transforms the non-uniform stress field of the shallow surrounding rock into a uniform stress field. PSCR-NPR is applied in the fault-through roadway of Daqiang mine. The low stress area of the surrounding rock was enlarged by 3-7 times, and the cumulative convergence was reduced by 45%-50%. It provides a reference for the stability control of the deep fault-through mining roadway.

NPR新材料钢在动态冲击载荷下的力学性能研究

为了研究NPR新材料钢在动态冲击载荷作用下的力学性能,利用分离式霍普金森杆装置对其进行动态拉伸和动态压缩试验,通过试验获得材料的变形机理、失效模式及不同应变率下的应力-应变关系;并将试验结果与921A钢进行对比,分析2种材料的力学性能差异。研究结果表明,在准静态载荷作用下,NPR新材料钢具有较大的极限强度和断裂应变;在动态冲击载荷作用下,NPR新材料钢的屈服强度和极限强度均随应变率的增加而增大,表现出较强的应变率效应,且在高应变率下,NPR新材料钢的应变率强化效应更显著,具有较好的静、动态力学性能。

烟草NPR1基因家族鉴定及其在南方根结线虫胁迫下的表达分析

本研究旨在挖掘烟草抗南方根结线虫病程相关基因非表达子NPR1(non-expressor of PR genes)家族成员,并明确其功能。基于拟南芥AtNPR1家族成员蛋白序列,利用生物信息学方法鉴定分析烟草NtNPR1基因家族成员及其特征。通过qRT-PCR检测南方根结线虫侵染后抗病(NC95)、感病(长脖黄)烟草品种Nt-NPR1家族重要候选抗性基因的相对表达量,采用LC-MS/MS方法对2个品种烟草根系内源水杨酸含量进行检测。结果表明,从普通烟草基因组中共鉴定到12个NtNPR1基因,这些基因被分为3个亚组,同一亚组中NtNPR1家族成员蛋白结构、保守基序的长度和位置都极为相似。编码氨基酸长度范围为462~588,均为亲水性蛋白,均位于细胞核。南方根结线虫侵染抗、感烟草品种后,根系中水杨酸含量、NtNPR1基因家族成员表达量在抗病品种中均升高,在感病品种中则降低,其中NtNPR6的变化最为明显。综上,NPR1基因与烟草南方根结线虫抗性密切相关,NtNPR6基因可作为烟草响应南方根结线虫胁迫的重要基因。

NPR钢板材多性能试验研究

开展NPR钢主要力学性能试验研究,并将其相关性能与舰用921A钢进行对比。结果表明:NPR钢具备较高的拉伸强度,同时还保持着优异的韧性,其面内方向吸收能量的能力较强;在高应变速率条件下,NPR钢的屈服强度和极限强度均有较大提高,表现出较强的应变率敏感性。此外,NPR钢材的耐腐蚀性能、冷弯曲加工性能和低磁/无磁性能均表现优异。研究结果表明:NPR钢的综合性能较好,尤其适合应用于对大变形、高应力和高延性有较高要求的工程场景,在舰船抗爆和抗冲击等领域有较好的应用预期。

Case study on the mechanics of NPR anchor cable compensation for large deformation tunnel in soft rock in the Transverse Mountain area,China

A study was conducted to analyze the deformation mechanism of strongly weathered quartz schist in the Daliangshan Tunnel,located in the western Transverse Mountain area.A large deformation problem was experienced during the tunnel construction.To mitigate this problem,a support system was designed incorporating negative Poisson ratio(NPR)anchor cables with negative Poisson ratio effect.Physical model experiments,field experiments,and numerical simulation experiments were conducted to investigate the compensation mechanical behavior of NPR anchor cables.The large deformations of soft rocks in the Daliangshan Tunnel are caused by a high ground stress,a high degree of joint fracture development,and a high degree of surrounding rock fragmentation.A compensation mechanics support system combining long and short NPR anchor cables was suggested to provide sufficient counter-support force(approximately 350 kN)for the surrounding rock inside the tunnel.Comparing the NPR anchor cable support system with the original support system used in the Daliangshan tunnel showed that an NPR anchor cable support system,combining cables of 6.3 m and 10.3 m in length,effectively prevented convergence of surrounding rock deformation,and the integrated settlement convergence value remained below 300 mm.This study provides an effective scientific basis for resolving large deformation problems in deeply buried soft rocks in western transverse mountain areas.

End-to-End Paired Ambisonic-Binaural Audio Rendering

Binaural rendering is of great interest to virtual reality and immersive media. Although humans can naturally use their two ears to perceive the spatial information contained in sounds, it is a challenging task for machines to achieve binaural rendering since the description of a sound field often requires multiple channels and even the metadata of the sound sources. In addition, the perceived sound varies from person to person even in the same sound field. Previous methods generally rely on individual-dependent head-related transferred function(HRTF)datasets and optimization algorithms that act on HRTFs. In practical applications, there are two major drawbacks to existing methods. The first is a high personalization cost, as traditional methods achieve personalized needs by measuring HRTFs. The second is insufficient accuracy because the optimization goal of traditional methods is to retain another part of information that is more important in perception at the cost of discarding a part of the information. Therefore, it is desirable to develop novel techniques to achieve personalization and accuracy at a low cost. To this end, we focus on the binaural rendering of ambisonic and propose 1) channel-shared encoder and channel-compared attention integrated into neural networks and 2) a loss function quantifying interaural level differences to deal with spatial information. To verify the proposed method, we collect and release the first paired ambisonic-binaural dataset and introduce three metrics to evaluate the content information and spatial information accuracy of the end-to-end methods. Extensive experimental results on the collected dataset demonstrate the superior performance of the proposed method and the shortcomings of previous methods.

Mechanism of high-preload support based on the NPR anchor cable in layered soft rock tunnels

The control of large deformation problems in layered soft rock tunnels needs to solve urgently.The roof problem is particularly severe among the deformation issues in tunnels.This study first analyzes the asymmetric deformation modes in layered soft rock tunnels with large deformations.Subsequently,we construct a mechanical model under ideal conditions for controlling the roof of layered soft rock tunnels through high preload with the support of NPR anchor cables.The prominent roles of long and short NPR anchor cables in the support system are also analyzed.The results indicate the significance of high preload in controlling the roof of layered soft rock tunnels.The short NPR anchor cables effectively improve the integrity of the stratified soft rock layers,while the long NPR anchor cables effectively mobilize the self-bearing capacity of deep-stable rock layers.Finally,the high-preload support method with NPR anchor cables is validated to have a good effect on controlling large deformations in layered soft rock tunnels through field monitoring data.

A Fast and Memory-Efficient Direct Rendering Method for Polynomial-Based Implicit Surfaces

Three-dimensional surfaces are typically modeled as implicit surfaces.However,direct rendering of implicit surfaces is not simple,especially when such surfaces contain finely detailed shapes.One approach is ray-casting,where the field of the implicit surface is assumed to be piecewise polynomials defined on the grid of a rectangular domain.A critical issue for direct rendering based on ray-casting is the computational cost of finding intersections between surfaces and rays.In particular,ray-casting requires many function evaluations along each ray,severely slowing the rendering speed.In this paper,a method is proposed to achieve direct rendering of polynomial-based implicit surfaces in real-time by strategically narrowing the search range and designing the shader to exploit the structure of piecewise polynomials.In experiments,the proposed method achieved a high framerate performance for different test cases,with a speed-up factor ranging from 1.1 to 218.2.In addition,the proposed method demonstrated better efficiency with high cell resolution.In terms of memory consumption,the proposed method saved between 90.94%and 99.64%in different test cases.Generally,the proposed method became more memoryefficient as the cell resolution increased.

配置NPR钢筋的混凝土构件受弯计算方法研究

NPR(负泊松比)钢筋是一种新型高强度钢筋,屈服强度标准值大于625 MPa,其抗拉强度与抗压强度不等。为研究NPR钢筋在混凝土受弯构件中的应用,根据钢筋的本构关系,利用平截面假定推导并得出了界限受压区高度;推导了单筋梁的最大配筋率、双筋梁受压筋与受拉筋的相对关系;推导了受弯构件正截面计算方法。结果表明,对于混凝土受弯构件,配置NPR钢筋的计算方法与配置普通热轧钢筋不同。提出了现有结构计算软件存在的问题,提出了配置NPR钢筋的矩形截面受弯构件的处理措施。研究结果可为NPR钢筋在工程中的推广应用提供参考。

Research and Application of Caideng Model Rendering Technology for Virtual Reality

With the development of virtual reality (VR) technology, more and more industries are beginning to integrate with VR technology. In response to the problem of not being able to directly render the lighting effect of Caideng in digital Caideng scenes, this article analyzes the lighting model. It combines it with the lighting effect of Caideng scenes to design an optimized lighting model algorithm that fuses the bidirectional transmission distribution function (BTDF) model. This algorithm can efficiently render the lighting effect of Caideng models in a virtual environment. And using image optimization processing methods, the immersive experience effect on the VR is enhanced. Finally, a Caideng roaming interactive system was designed based on this method. The results show that the frame rate of the system is stable during operation, maintained above 60 fps, and has a good immersive experience.

基于NPR水墨风格动画的中国古建筑文化的传承与创新

近些年,新兴的NPR(非真实感绘制)水墨风格动画以其独特的风格引起了强烈的反响。水墨风格是展示中国传统文化的代表性绘画风格之一。因此,以NPR动画为载体的水墨风格展现中国古建筑美观、实用等多方面的风采成为可能。该文整理归纳当前NPR水墨风格动画的研究,用动画形式展示传统古建筑的美,旨在为古建筑的展现形式和传统建筑文化传承寻找新思路。

深部井巷工程高预应力NPR耦合支护技术

深部煤炭资源是未来我国能源安全的重要保证,但受深部“三高一复杂”地质力学环境影响,深部井巷工程岩体大变形失稳问题日渐突出。为解决该问题,以支护-围岩相互作用为突破点,研发了具有高强度、高恒阻、大变形力学特性的系列NPR锚杆/索,构建了NPR锚杆的本构方程,并开展室内和现场综合力学试验,验证了NPR锚杆/索的独特力学特性;分析了NPR支护-围岩相互作用关系,推导了NPR支护岩体本构关系,阐明了采用NPR耦合支护后的开挖补偿力学效应,揭示了高预应力NPR耦合支护机理;结合大强煤矿实际工况,提出了深部泵房吸水井以NPR锚杆/索为核心的集约化硐室群NPR支护技术。数值分析和现场监测数据显示:高预应力NPR耦合支护技术可显著提高支护-围岩的承载特性,有效减小井巷工程岩体塑性区的分布及发展范围;支护后支护-围岩应力场趋于均匀化,围岩整体变形量减小68%以上,确保了深部井巷工程岩体的长期稳定。研究成果可为类似条件下的深部井巷工程稳定性控制提供借鉴。

万福矿深埋大断面T型交叉点高预应力NPR支护机制及应用

为解决深部大断面软岩巷道交叉点大变形问题,以万福煤矿千米深井巷道交叉点为工程实例,首次在巷道支护中运用微观负泊松比(negative Poisson’s ration,NPR)钢锚索。采用室内试验、理论分析、数值模拟及现场试验相结合的方法,分析了深埋巷道交叉点的围岩变形机制,提出了以微观NPR钢锚索为核心的控制对策。通过室内静力拉伸试验对微观NPR钢锚索的力学特性进行研究,结果表明,微观NPR钢锚索拉伸全过程表现为高恒阻,均匀拉伸,无屈服平台,破断时无明显颈缩现象。通过理论推导,基于T型巷道交叉点围岩最大影响范围,建立微观NPR钢锚索支护T型巷道交叉口最大影响范围计算模型。通过数值模拟,再现T型巷道交叉口的破坏演化过程,分析对比普通支护/微观NPR钢锚索支护效果。现场开展支护应用试验与监测,验证了长短微观NPR钢锚索联合支护对策具有良好的交叉口围岩大变形控制效果,为交叉口围岩安全稳定控制提供了新支护材料和支护手段。

富水断层带隧道变形力学机制及双梯度注浆NPR补偿对策

云南他白依隧道位于青藏高原东麓,穿越多条断层构造带,其围岩软弱破碎,遇水强度骤降。原设计方案下围岩存在米级大变形,出现了拱架扭曲、仰拱隆起和突泥涌水等灾害。针对富水断层带隧道围岩破碎难题,首先通过矿物成分分析、点荷载试验及地应力测试,分析了富水断层带隧道变形力学机制及其转化,通过未注浆、常规注浆及双梯度注浆的围岩承载力试验,确定采用双梯度注浆工艺进行NPR锚索锚固;然后,通过数值模拟及现场试验,得出了最佳锚索数目;最后,通过现场应用,基于监测数据验证了双梯度注浆及高预紧力长短NPR锚索支护体系的可靠性。研究结果可为类似富水断层带隧道的大变形灾害控制提供参考。