橡胶颗粒土动剪模量与阻尼比的共振柱试验研究

废旧轮胎橡胶颗粒与砂土组成的橡胶颗粒土相比于纯砂而言,具有密度轻、弹性变形能力强、耗能大、剪切模量低等特点,可广泛应用于边坡、挡土墙和路基回填、桥台跳车治理以及建筑隔震减振等工程领域。通过共振柱试验,重点对比研究了橡胶含量、粒径及围压对混合土动剪切模量和等效阻尼比的影响规律。结果表明,小应变范围内,在围压和粒径相同时,随橡胶含量的增加,橡胶土动剪切模量减小,阻尼比增大,动剪模量比衰退变缓;含量和粒径相同时,围压增大,动剪模量增大,动剪模量比衰退变缓,阻尼比减小。在大应变幅值下,橡胶含量较低时,随着围压增大,动剪模量比衰退明显加快;而当橡胶含量较高时,围压对其影响与小应变范围相同;而围压与橡胶含量相同时,不同橡胶粒径的模量与阻尼比曲线非常接近。橡胶土的动剪模量与阻尼比主要受橡胶含量与固结围压影响,而粒径影响可忽略不计。     

基于拟动力法抗滑桩加固非饱和土边坡稳定性分析∗

基于极限分析上限原理和拟动力法,提出一种半解析改进水平片分法,计算具有非线性分布特征的非饱和土重力和地震惯性力所做外功率,将传统塑性理论扩展至非饱和土中以考虑基质吸力对桩侧阻力的提升作用,与解析解对比验证了该方法的合理性。通过算例分析,揭示了吸力对非饱和土边坡稳定性及抗滑桩加固效果的强化作用,探究了非饱和土边坡的地震响应规律,研究了抗滑桩布设参数对支挡结构边坡稳定性的影响规律。研究结果表明：吸力对边坡稳定性的提升效果可达 20% ~ 50%,吸力效应与地震动特性密切相关,在地震波达到峰值时显著增强;水平和竖向加速度系数以及土剪切模量对边坡地震稳定性影响较大;桩距 D₁/d_p ≤ 4 时,抗滑桩加固效果较为显著并随摩擦角的增加得到强化,抗滑桩最佳桩位位于边坡中上部,且随摩擦角的增加逐渐减小,对应的加固效果也有所降低。     

Are energy conservation and emission reduction policy measures effective for industrial structure restructuring and upgrading?

The use of energy conservation emission reduction policies to promote industrial restructuring and upgrading and thus facilitate energy conservation and emission reduction is one of the 10 important strategies of environmental management in China. The use of energy conservation emission reduction policies to promote industrial restructuring and upgrading and thus facilitate energy conservation and emission reduction is one of the important strategies of environmental management in China. Based on the systematic collection of 1,195 energy conservation emission reduction policies, we discuss the influence of individual measure and measure synergy of energy conservation and emission reduction policies respectively. The results show that the energy conservation and emission reduction policies have a significant effect on the overall promotion of industrial upgrading. The financial measures and guidance measures have a positive impact; the financial measures and guidance measures have significantly positive effect; however, the administrative measures, fiscal tax measures, and other economic measures do the opposite; the positive effect of the synergy of guidance measures and financial measures is greater than the negative effect of considering only the synergy of fiscal tax measures and other economic measures, and significantly greater than the negative effect of the synergy of administrative measures, fiscal tax measures, and other economic measures. We should strengthen and emphasize the use of the measure that has positive effect on industrial structure restructuring and upgrading individually and synergistically.     

苏州深厚场地等效剪切波速与计算深度分析

剪切波速是表征土体动力特性的重要参数,通常抗震规范将其作为场地分类的主要指标,但不同规范选取的计算深度有所差异。基于苏州研究区446个钻孔的波速实测资料,统计分析了相对于计算深度20m和30m的等效剪切波速v_(s,20)和v_(s,30)的相关性;依据中国规范、欧盟规范和美国规范给出的场地分类标准,比较了不同抗震规范下苏州研究区场地分类空间分布特征。结果表明:苏州研究区场地的vs,20和vs,30之间存在良好的线性关系,其线性回归分析的决定系数R~2为0.888;中国规范和欧美规范给出的场地分类空间分布的差异性明显,中国规范的Ⅱ类场地分布于研究区西部局部区域、Ⅲ类场地分布于整个研究区、Ⅳ类场地呈零星分布;欧盟规范的CEU类和美国规范的DUS类场地分布于整个研究区,而欧盟规范的DEU类和美国规范的EUS类场地主要分布于与东西向呈23°夹角的一个狭长区带内。     

金塘海峡海洋土动剪切模量与阻尼比特性研究∗

为探究金塘海峡各类海洋土的动剪切模量G与阻尼比λ特征,对金塘海峡四个钻孔不同埋深的各类原状海洋土进行了系列室内共振柱试验,试验结果表明:(1)各类海洋土均呈现出"低剪切模量,高阻尼比"的强非线性与滞后性特性;各类海洋土的最大动剪切模量G_(max)均随埋深的增加而增大,且粉质黏土、粉土、粉质黏土混粉砂、粉砂的G_(max)随埋深的增长速率依次减慢。(2)随着埋深的增加,各类海洋土的G/G_(max)―γ曲线移向右上侧,非线性特性减弱;相反,λ—γ曲线移向右下侧,土体的滞后性减弱。(3)给出了金塘海峡各类海洋土G/G_(max)―γ和λ—γ曲线随埋深变化的参数值。     

农药对藻类的生态毒理学研究Ⅱ:毒性机理及其富集和降解

随着对农药污染认识的深入,农药对生态系统的初级生产者———藻类毒性以及毒性机制的研究不断增多。农药对藻类的毒性在于破坏藻类生物膜的结构和功能、影响藻类的光合作用、改变呼吸作用以及固氮作用,影响藻类的生理进程并改变其生化组分。开展农药对藻类毒性机理的研究,揭示农药结构—活性关系,对农药的研制和应用,评价农药的生态风险,减少农药对藻类的毒害是重要的。在自然环境中还发现藻能富集和降解农药。因此,对于这些藻来说,农药对藻类的毒害作用和藻类对农药的富集和降解作用可能同时存在。本文综述了农药对藻类的毒性机理以及藻类对农药的富集和降解作用。     

可液化地基群桩基础地震反应总应力与有效应力分析的比较

可液化土体动力特性的描述方法可能对群桩基础动力反应产生显著的影响。基于Davidenkov本构模型和Byrne改进的增量孔压模型,对比分析了总应力法和有效应力法计算的可液化地基中群桩基础地震反应特性。结果表明,群桩外侧地基最易液化,自由场地基次之,群桩内地基土最不易液化;与总应力法的计算结果相比,有效应力法计算得到的地表加速度反应谱谱值的短周期过滤和长周期放大效应更加显著,卓越周期向长周期方向移动;同时,有效应力法计算得到的桩身弯矩也有所增大。     

浅析电除尘设备常见故障与排除

本文对电除尘器在使用过程中影响除尘性能的机械、电气和辅助设施等常见故障,分别进行剖析,并提出相应处理办法,以期将已投产使用的电除尘设备,在治理烟（废）气、净化空气、保护环境、回收有价粉尘以充分利用有限的自然资源等方面,发挥更大作用。     

深厚第四纪沉积土非线性性能对地表地震动特性的影响∗

土体非线性性能对地表地震动的影响主要体现在其频谱成分和强度的改变上。采用修正Matasovic本构模型描述土的动力非线性特性,利用专业软件DeepSoil对深厚场地的50个钻孔剖面土柱模型进行了场地地震反应分析。采用加速度反应谱卓越周期T_p、平均谱周期T_avg及加速度傅氏谱平均周期T_m表征地表地震动频谱特性;以Arias强度I_a和地表峰值加速度PGA表征地表地震动强度。结果表明：(1) 特定场地条件下,T_p不能反映土体非线性对地震动从基岩传播至地表时频谱成分变化的影响;T_avg和T_m在表征地震动频谱成分特性时具有较高的一致性;(2) 基岩地震动高频丰富时,T_avg和T_m随着基岩地震动峰值加速度的增大而呈现出线性增长的趋势;而基岩地震动低频较发育时,T_avg和T_m的增长趋势线存在明显的拐点;（3）PGA与I_a值随基岩地震动峰值加速度的增大呈现出基本一致的非线性增长趋势,且其离散性均随基岩峰值加速度的增大而增大。     

Spatial effect of environmental regulation measures on industrial structure upgrading from the empirical analysis of Beijing-Tianjin-Hebei region and its surrounding areas

ABSTRACT

This paper investigates the spatial effect of environmental regulation measures on the upgrading of industrial structure in the integrated development strategy of Beijing-Tianjin-Hebei region and its surrounding areas. In order to reflect the effect of the environmental regulation and different regulation measures more truly, this paper constructs indices of the environmental regulation measures through the results of policy texts quantification. On the basis of the previous research, this paper divides environmental regulation into the following types: personnel and administrative measures of command and control; market-oriented fiscal, taxation, financial and other economic measures; guidance measures. Spatial panel regression results show that administrative measures of command control and market-oriented fiscal measures have a significant role in promoting regional industrial structure upgrading, but not conducive to the advancement of the industrial structure of adjacent areas. Their roles in promoting and inhibition are counteracted, which causes the total effect of industrial structure upgrading of Beijing-Tianjin-Hebei and the surrounding areas are not significant. Personnel measures, financial measures, other economic measures and guidance measures do not have the short-term effect and spatial effect on the upgrading of industrial structure.