简介:随着我国地下空间的持续开发,穿江越河及邻江邻河的地下工程项目越来越多,这类项目往往伴随邻山且邻水的工程特定环境,其深基坑工程变形机制和影响效力尚不明确,相关控制手段亦少有研究.依托杭州市某紧邻钱塘江的市政隧道工程,考虑潮汐波动影响对 36.4m超深大偏载基坑变形进行了三维数值模拟分析,提出相应变形控制方法并进行工程实践.研究表明:通过依托工程基坑内外水位监测数据的理论分析和数值求解,建立基坑渗流场时空演化模型,得知潮汐水流进入土层边界时的水头衰减较大,在渗流路径中,水头变化较稳定,基坑附近地下水对潮汐循环荷载的响应有明显滞后性,基坑周围产生较高孔隙水压力.运用有限元软件采用修正Mohr-Coulomb弹塑性本构模型,建立偏载深基坑开挖及周围环境影响的数值模拟三维模型,为模拟潮汐波动带的影响,简化在基坑河流底部分别施加 25kPa和 6...Abstract:With the continuous development of underground space in China,there are increasingly more underground engineering projects crossing or adjacent to rivers.Such projects are often accompanied by the unique environment of the project adjacent to the mountains and rivers,whose deformation mechanisms and influence effects of deep foundation pit engineering are not clear,and their relevant control methods are rarely studied.Based on a municipal tunnel project adjacent to the Qiantang River in Hangzhou,the seepage law of the tidal wave zone was systematically studied.The numerical simulation analysis of the deformation of the 36.4 m ultra-deep and large eccentric load foundation pit wa.
简介:报道了用水热法合成直接甲醇燃料电池(DMFC)阴极碳载Pd-Fe(Pd-Fe/C)催化剂,利用X射线衍射仪(XRD)和透射电子显微镜(TEM)对催化剂进行了结构表征;结果表明:水热法合成的Pd-Fe/C催化剂中的金属粒子,其平均粒径较小,分散均匀;电化学测试表明:Pd-Fe/C催化剂对氧还原反应有很高的电催化活性。