北京地区典型砖木结构农宅抗震加固性能研究

根据北京地区农村住宅调研结果,选取最典型的砖木(前檐砖柱支撑)结构,进行了加固前后的振动台试验。针对北京地区农村住宅砖木结构(砖柱支撑)未加固模型的振动台试验结果,提出了抗震加固措施,包括：加设钢筋混凝土窗框,增大前纵墙的抗侧刚度;采用水泥砂浆面层加固两面山墙、砖柱和窗下墙,提高墙体的承载和变形能力;加设钢圈梁,提高结构的整体牢固性。分析了模型加固前后振动台试验的损伤情况、频率和阻尼、加速度动力系数、位移和滞回曲线等结构动力特性参数。上述加固措施显著提高了此类砖木结构农宅的抗震能力,加固模型达到了“小震不坏、中震可修、大震不倒”的抗震设防目标。     

Axial Force Stiffness Interaction in Seismic Analysis of RC Double Column Bridges

Earthquake induced dynamic axial force in reinforced concrete (RC) bridge bent columns will not only change the yield strength of the columns but also change their stiffness, which is seldom considered by the common lumped plasticity line model. Based on the fiber element model results that taking into account the influence of dynamic axial force on strength and stiffness simultaneously, the axial force stiffness interaction effect on the seismic responses of RC double column bridges was analyzed. The results show that, axial force stiffness interaction has a large effect on the seismic responses of the double column bridge in the elastic range, and it does not alter the ultimate capacity of the columns. Since the stiffness of the columns under compression and tension dynamic axial forces offset each other, the global displacement of bridge bent with equal columns is relatively unaffected by the axial force stiffness interaction, however, the differences of the column member forces are manifest. For the short column controls the global stiffness, the axial force stiffness interaction has significant influences on both the global displacement and member force responses. The influences become larger as the irregularity of the bridge bent increases, so the interaction between axial force and member stiffness should be sufficiently considered in seismic analyses.     

四川震区土地整理安全性评价及措施

四川汶川地震及引发的次生地质灾害造成四川全省22 701个村受灾,耕地损毁约129 500 hm2,建设用地损毁约114 500 hm2,灾后重建任务艰巨。土地整理是实施灾后重建的有效手段,而安全性评价是开展灾后土地整理和灾后土地利用的基础。该文对四川震区灾后重建土地整理安全性评价的因素进行了分析,选择距发震断裂带距离、岩土体类型、相对高差、地形坡度等作为土地整理安全性评价指标,根据发生灾害的危险程度,对影响因素进行危险程度分级。采取单因素评价叠加法将四川震区划分为土地整理高危险区、土地整理中危险区、土地整理一般危险区。高危险区主要位于龙门山地震活动断裂带200 m以内,相对高差500 m以上,地形坡度＞25°的中高山峡谷地区;中危险区主要位于地震断裂带200～500 m,相对高差200～500 m,地形坡度介于15°～25°的低山丘陵地区;低危险区主要位于地震断裂带500 m以外,相对高差低于200 m,地形坡度＜15°的浅丘平原地区。同时该文针对各区域土地损毁和利用特点提出了灾后重建土地整理措施。     

西安地区地下热水季节性活动与区域地震活动的关系研究

根据西影井热水水位的观测资料,分析了西安地区地下热水活动的季节性特征及其与区域地震活动的相关性。结果表明西安地区地下热水活动与区域地震活动明显相关,其相关性基本不受季节性用水的影响,反映出它们受同一构造力源的控制,同时,西安地区地下热水活动与西安及邻区的地震活动最为密切。     

粗集理论中基于差别矩阵的属性约简算法

在传统差别矩阵的基础上,提出了改进的差别矩阵属性约简算法和基于逻辑差别矩阵的属性约简算法,提高了生成差别矩阵时的效率,减少了存储差别矩阵所用的存储空间,并提出了基于回溯思想的逻辑差别矩阵属性约简算法,得到最小约简。     

Improved algorithm of contact element model for earthquake-induced pounding between structures

To better study the issue, we presented an improved algorithm. In this algorithm, the impact issue is equivalent to a spring〖XC半字线.tif,JZ〗oscillator model which contains an oscillator, a spring and a damper. The oscillator movement represents the compression phase and restitution phase of impact. By solving the motion equation, we got the penetration displacement,penetration velocity, impact force, impact time and their mutual relationship. The solution process did not carriy out the hypothesis that the energy dissipation or absolute speed during the restitution phase is the same as that during the compression phase, which was adopted by common solution methods. Therefore we can get the exact results or approximate results that are infinitely close to the exact results. In the case of small energy dissipation during the collision, Hertzdamp model results obtaind by common solution methods are close to the exact results. When the energy dissipation during the collision is large, the difference between them becomes obvious. Regardless of small or large energy dissipation during the collision, the improved algorithm can obtain the results which are infinitely close to the exact results. 〖BP(〗Therefore, the improved algorithm has more advantages than common solution methods, especially for solving the earthquake-induced pounding problems with a large number of energy dissipation during the collision.〖BP)〗     

基于粗糙集属性重要性的农村居民点整理潜力评价——以兰州市七里河区为例

采用粗糙集的属性重要性原理评价了兰州市七里河区农村居民点整理潜力。结果表明:属性重要性原理可以消除冗余指标,知识集合的重要性原理可以确定不同层次评价指标的权重,粗糙集的属性重要性可以为土地评价提供一种新的途径。     

天然白桦林直径分布规律的研究

在林分生长模型研究中，选择描述林分直径分布的函数是至关重要的。本文对来自于内蒙古地区的天然白桦林林分用不同的函数对直径分布进行验证，根据检验结果表明：正态分布接受率最高；同时对结果也做了分析，探讨了不同年龄、不同立地指数对正态分布接受率的影响；并对不接受分布的原因进行了简单的分析。     

社会和谐：中国特色社会主义的本质属性

社会和谐是科学社会主义的题中要义，是中国特色社会主义的本质属性。要把不断促进社会和谐、不断提高社会和谐程度作为贯穿中国特色社会主义事业全过程的长期历史任务。     

大跨度钢管混凝土拱桥空间地震响应分析

建立了四川白日坝大桥的空间有限元模型,研究了该桥的自振特性并讨论了结构主要参数对其动力特性的影响,然后对该桥在一致激励、行波效应、多点激励下的结构响应进行了分析,并考虑了几何非线性对结构地震响应的影响.得出了一些有益于工程的结论.