带翼缘板圆形钢管顶进土体扰动规律研究

STS(Steel Tube Slab)管幕法以带翼缘板的圆形钢管密集顶进形成基本骨架,管间穿入连接螺栓并灌注混凝土。管间螺栓、翼缘板将各钢管连为一体,管幕横向刚度显著提高。带翼缘板的圆形钢管顶进引起的土体扰动更为强烈。本文基于弹性力学圆孔扩张理论,提出了带翼缘板圆形钢管的管周塑性区计算公式,进而得到适用于沈阳地层的土体扰动度半径的计算方法。通过静力触探原位试验,进一步研究了带翼缘板钢管管周边土体扰动影响程度。通过试验结果和理论计算进行对比分析,两者得到的扰动半径分别为1.51 m和1.32 m,吻合度较高。验证了本文提出管周塑性区计算公式的合理性。     

无人机航测在风景园林中的应用研究

近年来随着民用无人机的普及,无人机开始越来越多地应用于风景园林领域中。但目前大多数应用还停留在基础的航拍层面,对于应用潜力更大的航测层面,在风景园林行业中的应用相对较少,也更鲜为人知,现有研究更多聚焦于具体案例的应用方面,未能对其进行系统的认知和介绍。简要介绍无人机航测与遥感系统的构成及常见传感器类型,通过文献综合、项目实践等方法,系统地整理了国内外无人机航测相关的研究与应用进展,进而总结出无人机航测在风景园林中的应用可分为传统航测、倾斜摄影、多种传感器遥感3个方面。最后指出传统航测发展最为成熟,短时间内推广应用的可能性最大;倾斜摄影效率最高;多种传感器遥感未来开发潜力最大。以期对今后无人机在风景园林中的应用与研究有所启发。     

Numerical verification of the continuous calculation method for tip stress during the driving process of the dynamic penetration test

This paper presents a calculation method for obtaining the continuous variation in stress between the tip and the soil during dynamic penetration tests, particularly in the case of using the Panda 3® penetration testing device. The originality of the method is that the tip stress can be computed continuously throughout the driving process. For each impact of the hammer on the penetrometer, data are recorded by sensors located at the top of the apparatus. Then, the stress at the tip and the displacement of the apparatus are calculated with a method based on the propagation of waves in the device. A three-dimensional numerical model of the penetration test, based on the Panda 3® specifications and using the discrete element method (DEM), is proposed in this paper. The purpose of the simulations is to validate the calculation method by comparing the curves of the tip stress versus the penetration distance obtained in two different ways, the first being the distance directly observed at the tip and the second being the distance calculated from the data recorded at the top of the penetrometer, as with the experimental device. The entire apparatus is represented, including the hammer, the rod, and the tip, and is driven into the model soil. The calculation method is applied, and the results are compared to the actual response of the soil to the driving of the penetrometer directly at the tip, which can be obtained with the numerical model. The responses are found to be very similar, confirming the theoretical framework and its underlying assumptions. This method is applied to dynamic penetration tests and provides the opportunity to obtain mechanical parameters other than the tip resistance from the tests.     

装配式型钢斜交密肋复合墙抗震性能试验研究

与传统的密肋复合墙相比,装配式型钢斜交密肋复合墙是用型钢代替钢筋作为墙体肋格内的骨架,并采用斜交肋格形式形成的一种改进型密肋复合墙。为了验证该类墙体的抗震性能,进行了4个1/2比例密肋复合墙体试件的拟静力试验,基于试验分别对不同肋格骨架材料和不同肋格形式的密肋复合墙在低周往复荷载下的破坏模式、滞回特性、受剪承载力、变形能力、刚度退化和耗能能力等进行对比分析。研究结果表明：各试件破坏基本遵照“砌块-肋格-边框柱”三道抗震防线的路径,破坏形态为整体剪切破坏;采用型钢骨架和斜交肋格均能大幅提高密肋复合墙的受剪承载力和抗侧刚度,同时也能够使墙体具有良好的耗能能力;型钢斜交密肋复合墙和传统密肋复合墙的变形能力基本一致。研究为装配式密肋复合板结构的进一步优化设计与推广应用提供了试验及理论基础。     

液塑限联合测定法的应用与研究

本文对落锥法与液塑限联合测定法测定土的液塑限进行了对比试验研究。土样来自北京周边地区,共400余组。试验结果表明:对于粉土,误差范围大部分在-1～1之间;对于粉质粘土,误差范围大部分在-1～2之间;对于粘土,误差范围大部分在-1～5之间;两种方法液限的拟合曲线为y=1.0286x,相关系数为0.98,两种方法塑限的拟合曲线为y=1.0224x,相关系数为0.90。说明利用联合测定法取代搓条与落锥法在液塑限试验中是可行的。     

谈太原市博物馆干挂铝板—玻璃肋幕墙施工

太原市博物馆为不规则的椭圆倒锥体,致使其外墙幕墙工程施工难度大。本工程采用了敞缝干挂铝板—玻璃肋幕墙方法施工,有效地解决了开缝铝板幕墙施工中的难点问题,取得了良好的经济效益和社会效益。     

青田塔山大桥承台及V形墩施工技术

根据青田塔山大桥的基本概况,详细论述了承台及V形墩的施工方案及具体施工方法,工程实践证明：该施工方案是切实可行的,达到了预期的设计要求,解决了同类型桥梁施工难度大的问题。     

真空强排水联合低能量强夯动力固结法处理软土地基实例

真空强排水联合低能量强夯动力固结法具有施工简单、工期短、造价低、效益好等优点。文章主要介绍真空强排水联合低能量强夯动力固结法在上海海港新城一期市政道路及雨水管道工程地基处理中的应用,以该工程为例,全面介绍该工艺的设计、施工以及检测方法等。     

Soil seismic analysis for 2D oblique incident waves using exact free-field responses by frequency-based finite/infinite element method

The seismic analysis of a viscoelastic half-space under two-dimensional (2D) oblique incident waves is carried out by the finite/infinite element method (FIEM). First, the frequency-domain exact solutions for the displacements and stresses of the free field are derived in general form for arbitrary incident P and SV waves. With the present formulation, no distinction needs to be made for SV waves with over-critical incident angles that make the reflected P waves disappear, while no critical angle exists for P waves. Next, the equivalent seismic forces of the earthquake (Taft Earthquake 1952) imposed on the near-field boundary are generated by combining the solutions for unit ground accelerations with the earthquake spectrum. Based on the asymmetric finite/infinite element model, the frequency-domain motion equations for seismic analysis are presented with the key parameters selected. The results obtained in frequency and time domain are verified against those of Wolf’s, Luco and de Barros’ and for inversely computed ground motions. The parametric study indicated that distinct phase difference exists between the horizontal and vertical responses for SV waves with over-critical incident angles, but not for under-critical incident angles. Other observations were also made for the numerical results inside the text.     

历史文化街区、传统村落活化利用消防设计研究

摘 要：我国要求在城乡建设中系统保护、利用、传承好历史文化遗产,对于历史文化街区、传统村落的活化利用形成一批可复制可推广的经验。然而近年来相关火灾事故频发,火灾隐患整治和消防能力提升活动持续进行。归纳总结了国内外相关标准规范情况,针对历史文化街区、传统村落活化利用过程中消防设计难以遵照现行消防规范执行的现状,总结提炼出针对性消防设计的思路,从区域、建筑、监控管理三个层面提出消防设计策略。