土工材料力学性能对风积沙复合地基抗拔加固效果的影响
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摘要
为促进土工合成材料在输电线路工程地基处理中的选型应用,加固改良铁塔基础风积沙地基抗拔性能,通过室内钢塑土工格栅、塑料双向土工格栅、土工布加筋复合地基基础抗拔性能模型试验,并结合沙漠风积沙常规地基与加筋复合地基基础原位载荷试验中抗拔失稳时地表裂缝分布特征,研究了土工材料改良风积沙地基抗拔性能的加固机理;分析了筋材抗拉强度、伸长率及其与风积沙间摩擦系数性能指标对风积沙地基抗拔性能改良效果的影响。结果表明:复合地基土工材料有利于将基础荷载作用传递扩散至更大范围,通过筋材对基础底板的下拉作用实现基础抗拔性能的提升;筋材拉伸强度对地基抗拔能力提升影响较小,较大的伸长率会弱化地基抗拔加固效果,筋材与风积沙间摩擦系数越大地基抗拔加固效果更优。因此风积沙地基抗拔性能加固处理的筋材选型主要考虑伸长率和摩擦系数,钢塑土工格栅和塑料双向土工格栅的抗拔加固效果优于土工布。
In order to promote the geosynthetics selection application of the ground treatment in the transmission line engineering,strengthen the uplift resistant performance of the aeolian sand composite ground,the laboratory model tests on uplift performance of the composite foundations reinforced with the steel-plastic geogrid,plastic twoway geogrid and geotextile were carried out. Combining the surface crack distribution characteristics during the insitu uplift loading tests of the conventional aeolian sand foundation and the reinforced composite foundation under uplift failure,the reinforcement mechanism of improving the uplift resistance of aeolian sand ground with geotextile materials was studied. And the effects of tensile strength,elongation and friction coefficient of geosynthetics on the improvement of uplift resistance of aeolian sand foundation was analyzed. The results show that the geosynthetics in composite ground is beneficial to transfer and spread the foundation loading to a wider range,and the uplift performance of foundation is improved by the pull down effect of reinforced materials on the foundation slab,and the tensile strength of the geosynthetics has little influence on the improvement of the foundation uplift ability,and the larger elongation ratio can weaken the uplift reinforcement effect of the composite ground,and the greater the friction coefficient between the reinforced materials and aeolian sand is,the better the uplift reinforcement effect will be. Therefore,the elongation and friction coefficient should be taken into account in the selection of reinforcement materials for aeolian sand ground. And the reinforcement effect of the steel-plastic geogrid and the plastic two-way geogrid is better than the geotextile.
In order to promote the geosynthetics selection application of the ground treatment in the transmission line engineering,strengthen the uplift resistant performance of the aeolian sand composite ground,the laboratory model tests on uplift performance of the composite foundations reinforced with the steel-plastic geogrid,plastic twoway geogrid and geotextile were carried out. Combining the surface crack distribution characteristics during the insitu uplift loading tests of the conventional aeolian sand foundation and the reinforced composite foundation under uplift failure,the reinforcement mechanism of improving the uplift resistance of aeolian sand ground with geotextile materials was studied. And the effects of tensile strength,elongation and friction coefficient of geosynthetics on the improvement of uplift resistance of aeolian sand foundation was analyzed. The results show that the geosynthetics in composite ground is beneficial to transfer and spread the foundation loading to a wider range,and the uplift performance of foundation is improved by the pull down effect of reinforced materials on the foundation slab,and the tensile strength of the geosynthetics has little influence on the improvement of the foundation uplift ability,and the larger elongation ratio can weaken the uplift reinforcement effect of the composite ground,and the greater the friction coefficient between the reinforced materials and aeolian sand is,the better the uplift reinforcement effect will be. Therefore,the elongation and friction coefficient should be taken into account in the selection of reinforcement materials for aeolian sand ground. And the reinforcement effect of the steel-plastic geogrid and the plastic two-way geogrid is better than the geotextile.
引文
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9 程永锋,丁士君.沙漠地区风积沙地基输电线路装配式基础真型试验研究[J].岩土力学,2012,33(11):3230-3236Cheng Yongfeng,Ding Shijun. Prototype tests of assembly foundation of transmission line in aeolian sand area[J]. Rock&Soil Mechanics,2012,33(11):3230-3236
10 刘文白,周健,苏跃宏,等.加筋风砂土抗拔试验研究(I)-基本性质和扩展基础抗拔模型试验[J].岩石力学与工程学报,2003,22(7):1161-1168Liu Weibai,Zhou Jian,Su Yuehong,et al. Uplift test study on reinforced Aeolian sand(I)-properties and uplift model tests on spread foundation[J]. Chinese Journal of Rock Mechanics&Engineering,2003,22(7):1161-1168
11 刘文白,周健,刘霖,等.加筋风砂土抗拔试验研究(II)-抗拔载荷能力计算分析[J].岩石力学与工程学报,2004,23(3):430-435Liu Wenbai,Zhou Jian,Liu Lin,et al. Uplift test study on reinforced aeolian sand(II)-Analysis and calculation of uplift bearing capacity[J]. Chinese Journal of Rock Mechanics&Engineering,2004,23(3):430-435
12 乾增珍,鲁先龙,丁士君.上拔与水平力组合作用下加筋风积沙斜柱扩展基础试验[J].岩土工程学报,2011,33(3):373-379Qian Zengzhen,Lu Xianlong,Ding Shijun. Experiments on pad and chimney foundation in reinforced aeolian sand under uplift combined with horizontal loads[J]. Chinese Journal of Geotechnical Engineering,2011,33(3):373-379
13 侯鹏翔,郑卫锋,李维,等.输电线路沙漠地区偏心装配式基础的承载性能研究[J].工业建筑,2016,46(1):100-104Hou Pengxiang,Zheng Weifeng,Li Wei. Research on bearing capacity of eccentric assembly foundation of transmission line in desert area[J]. Industrial Construction,2016,46(1):100-104
14 水利部水利水电规划设计总院.土工合成材料应用技术规范:GB/T 50290—2014[S].北京:中国计划出版社,2014China Renewable Energy Engineering Institute. Technical code for application of geosynthetics:GB/T 50290—2014[S]. Beijing:China Planning Press,2014
2 吴正.风沙地貌与治沙工程学[M].北京:科学出版社,2003Wu Zheng. Aeolian landforms and sand control engineering science[M]. Beijing:Science Press,2003
3 牟献友,谷攀.国内风积沙工程特性研究综述[J].内蒙古农业大学学报(自然科学版),2010,31(1):307-310Mou Xianyou, Gu Pan. Review on engineering characteristics of wind-blown sand[J]. Journal of Inner Mongolia Agricultural University,2010,31(1):307-310
4 鲁先龙,丁士君,杨文智,等.沙漠风积沙地基扩展基础抗拔现场试验研究[J].水利与建筑工程学报,2017,15(5):20-25Lu Xianlong,Ding Shijun,Yang Wenzhi,et al. Uplift field load tests on spread foundations in aeolian sand area[J]. Journal of Water Resources&Architectural Engineering,2017,15(5):20-25
5 能源行业电网设计标准化技术委员会.架空输电线路基础设计技术规程:DL/T 5219—2014[S].北京:中国计划出版社,2014Technical Committee for Standardization of Power Grid Design in Energy Industry. Technical code for design of foundation of overhead transmission line:DL/T 5219—2014[S]. Beijing:China Planning Press,2014
6 鲁先龙,程永锋,丁士君.风积沙地基工程性质及其输电线路基础抗拔设计[J].电力建设,2010,31(7):46-50Lu Xianlong,Cheng Yongfeng,Ding Shijun. Property of aeolian sand and design of the uplift bearing capacity for the sand foundation of transmission line structures[J]. Electric Power Construction,2010,31(7):46-50
7 赵丽敏,袁玉卿,李伟,等.黄泛区粉砂土静力特性的试验研究[J].科学技术与工程,2014,14(15):254-258Zhao Limin,Yuan Yuqing,Li Wei,et al. Experimental study on static character of the silty soil in the yellow river flooded area[J].Science Technology&Engineering,2014,14(15):254-258
8 郭根胜,张雁,杜诗朦.水泥稳定风积沙基层抗剪强度试验研究[J].科学技术与工程,2017,17(15):322-326Guo Gensheng, Zhang Yan, Du Shimeng. Grassroots-level shear strength experimental study of aeolian sand with cement[J]. Science Technology&Engineering,2017,17(15):322-326
9 程永锋,丁士君.沙漠地区风积沙地基输电线路装配式基础真型试验研究[J].岩土力学,2012,33(11):3230-3236Cheng Yongfeng,Ding Shijun. Prototype tests of assembly foundation of transmission line in aeolian sand area[J]. Rock&Soil Mechanics,2012,33(11):3230-3236
10 刘文白,周健,苏跃宏,等.加筋风砂土抗拔试验研究(I)-基本性质和扩展基础抗拔模型试验[J].岩石力学与工程学报,2003,22(7):1161-1168Liu Weibai,Zhou Jian,Su Yuehong,et al. Uplift test study on reinforced Aeolian sand(I)-properties and uplift model tests on spread foundation[J]. Chinese Journal of Rock Mechanics&Engineering,2003,22(7):1161-1168
11 刘文白,周健,刘霖,等.加筋风砂土抗拔试验研究(II)-抗拔载荷能力计算分析[J].岩石力学与工程学报,2004,23(3):430-435Liu Wenbai,Zhou Jian,Liu Lin,et al. Uplift test study on reinforced aeolian sand(II)-Analysis and calculation of uplift bearing capacity[J]. Chinese Journal of Rock Mechanics&Engineering,2004,23(3):430-435
12 乾增珍,鲁先龙,丁士君.上拔与水平力组合作用下加筋风积沙斜柱扩展基础试验[J].岩土工程学报,2011,33(3):373-379Qian Zengzhen,Lu Xianlong,Ding Shijun. Experiments on pad and chimney foundation in reinforced aeolian sand under uplift combined with horizontal loads[J]. Chinese Journal of Geotechnical Engineering,2011,33(3):373-379
13 侯鹏翔,郑卫锋,李维,等.输电线路沙漠地区偏心装配式基础的承载性能研究[J].工业建筑,2016,46(1):100-104Hou Pengxiang,Zheng Weifeng,Li Wei. Research on bearing capacity of eccentric assembly foundation of transmission line in desert area[J]. Industrial Construction,2016,46(1):100-104
14 水利部水利水电规划设计总院.土工合成材料应用技术规范:GB/T 50290—2014[S].北京:中国计划出版社,2014China Renewable Energy Engineering Institute. Technical code for application of geosynthetics:GB/T 50290—2014[S]. Beijing:China Planning Press,2014