中南地区极端冰雪条件下电塔地基承载力研究
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摘要
2008年初,我国大部分地区遭受了百年一遇的冰雪灾害,这次冰雪灾害对于常年不受冰雪灾害影响的中南地区电网设施造成了很大程度的破坏,输变电塔地基也发生了各种形式的破坏。论文以地基承载力相关理论为基础,以冻土的温度、含水量、冻融循环次数三个变量为研究主线,输变电塔的地基承载力为研究核心,在阐述了冻土物理性质的基础上,分析了中南地区典型土体(粉质粘土)抗剪强度与温度、含水量、冻融循环次数三个变量之间的关系,即在0°～-12°温度范围内,含水量相同的土体,温度越低,其内聚力C和内摩擦角φ愈大,土体的抗剪强度也逐渐增大;含水量为17%～35%范围内,同一温度下,土体含水量越高,其内聚力C和内摩擦角φ愈小,土体的抗剪强度也逐渐减小;在冻融循环次数(8次)以内,温度和含水量都不变的情况下,土体随冻融循环次数的增加,其内聚力C减小。论文分析了温度、含水量、冻融循环次数三个因素对地基承载力的影响,得出含水量为对地基土承载力影响最为敏感;温度是对地基土承载力影响较为敏感的因素。
论文分别提出了温度、含水量、冻融循环次数与地基承载力之间的关系,提出了冻融土地基承载力的确定方法。采用极限平衡理论的太沙基极限承载力公式,建立了不同温度下含水量与地基土承载力之间的线性关系。分析了冻结-解冻温度下,《建筑地基基础设计规范》中的地基承载力系数的确定方法,依据修正后的《建筑地基基础设计规范》中的地基承载力公式,总结出不同冻结温度下的地基土承载力与0℃时的地基土承载力之间的比例关系表,不同解冻温度下的地基土承载力与-12℃时的地基土承载力之间的比例关系表,以此可求出任意温度下的地基土承载力。论文采用ANSYS7.0,对冰雪环境下输电塔基在不同工况下剪力、位移、总应变进行了数值模拟分析,模拟塔基在冰雪环境下内力的变化,并得出相应的结论:覆冰荷载对塔基的变形具有一定的影响,地表温度对塔基的影响较大;随着地表温度的降低,塔基最大位移量、XY平面最大剪应力和塔基在热-结构耦合条件下最大应变均呈逐渐增加趋势,并逐渐趋于某一稳定值;在塔基荷载和风荷载联合作用下,塔基与基础接触点出现明显的应力集中;
本论文的研究成果对中南地区在极端冰雪灾害时期,准确确定输电塔基的地基承载力具有一定的实际意义。
In early 2008, most regions of China suffered a big of snow disaster. The power grid in central south district which is not affected by ice and snow disaster perennial was destroyed by the big of snow disaster. And transmission tower foundation also changed all forms of destruction. Based on the base tilt factor related theory basis, the temperature, moisture content, freeze-thaw cyclic number of frozen soil are the research main, the base tilt factor of transmission tower is the core research. On the basis of the physical properties of frozen soil analyzed the relationship between the silty clay of central south district and three variables that are shearing strength, temperature, moisture content and freeze-thawcyclic number, namely at 0°~ 12°temperature range, the soil mass have the same moisture content, temperature is lower, the cohesion C and internal friction Angle phi is larger, the shearing strength of soil mass also gradually increased. When the moisture content was at 17% ~ 35% temperature range, the soil mass have the same temperature, moisture content is taller, its cohesion C and internal friction Angle phi are smaller, the shearing strength of soil mass also gradually decreased. When freeze-thaw cyclic number are less than 8, temperature and moisture content aer invariable, soil mass with the increase of number of freeze-thaw cyclic number, the cohesion C decreases. This paper analyzes the relationship between three factors which are temperature, moisture content and freeze-thaw cyclic number and the base tilt factor, it is concluded that a method to determine the base tilt factor of frozen-thaw soil. Using Terzaghi's formula of the limit equilibrium theory,the linear relationship between soil moisture at different temperatures and base tilt factor is established. Analysis the freeze and thaw temperatures, a method to determine the of base tilt factor. Based on the amended of base tilt factor formula, summarize that the proportional relation on the base tilt factor at different freezing temperatures and the base tilt factor at 0℃while the proportion relation on the base tilt factor at different thawing temperatures and the base tilt factor at - 12℃, which can give the base tilt factor at arbitrary temperatures. The paper use ANSYS7.0, under the environment of transmission Kentucky on snow and ice in different conditions shear and displacement, total strain was simulated analysis, simulation under the environment of internal force in ice and snow Kentucky changes, and corresponding conclusion drawn: Cladding ice load on the deformation of Kentucky has certain effect, and the surface temperature on the influences of Kentucky. As surface temperature decrease, the Kentucky maximum of displacement, the shear stress ratio of XY plane and Kentucky in hot - structural coupling conditions under the maximum stress ratio are tending to gradually increasing trend, and gradually become a steady value; In Kentucky load and wind load combination, Kentucky and basic contact point appears obvious stress concentration.
This paper researches on the central south district in extreme snow disaster period, to properly determine the transmission of Kentucky foundation bearing capacity has certain practical significance.
论文分别提出了温度、含水量、冻融循环次数与地基承载力之间的关系,提出了冻融土地基承载力的确定方法。采用极限平衡理论的太沙基极限承载力公式,建立了不同温度下含水量与地基土承载力之间的线性关系。分析了冻结-解冻温度下,《建筑地基基础设计规范》中的地基承载力系数的确定方法,依据修正后的《建筑地基基础设计规范》中的地基承载力公式,总结出不同冻结温度下的地基土承载力与0℃时的地基土承载力之间的比例关系表,不同解冻温度下的地基土承载力与-12℃时的地基土承载力之间的比例关系表,以此可求出任意温度下的地基土承载力。论文采用ANSYS7.0,对冰雪环境下输电塔基在不同工况下剪力、位移、总应变进行了数值模拟分析,模拟塔基在冰雪环境下内力的变化,并得出相应的结论:覆冰荷载对塔基的变形具有一定的影响,地表温度对塔基的影响较大;随着地表温度的降低,塔基最大位移量、XY平面最大剪应力和塔基在热-结构耦合条件下最大应变均呈逐渐增加趋势,并逐渐趋于某一稳定值;在塔基荷载和风荷载联合作用下,塔基与基础接触点出现明显的应力集中;
本论文的研究成果对中南地区在极端冰雪灾害时期,准确确定输电塔基的地基承载力具有一定的实际意义。
In early 2008, most regions of China suffered a big of snow disaster. The power grid in central south district which is not affected by ice and snow disaster perennial was destroyed by the big of snow disaster. And transmission tower foundation also changed all forms of destruction. Based on the base tilt factor related theory basis, the temperature, moisture content, freeze-thaw cyclic number of frozen soil are the research main, the base tilt factor of transmission tower is the core research. On the basis of the physical properties of frozen soil analyzed the relationship between the silty clay of central south district and three variables that are shearing strength, temperature, moisture content and freeze-thawcyclic number, namely at 0°~ 12°temperature range, the soil mass have the same moisture content, temperature is lower, the cohesion C and internal friction Angle phi is larger, the shearing strength of soil mass also gradually increased. When the moisture content was at 17% ~ 35% temperature range, the soil mass have the same temperature, moisture content is taller, its cohesion C and internal friction Angle phi are smaller, the shearing strength of soil mass also gradually decreased. When freeze-thaw cyclic number are less than 8, temperature and moisture content aer invariable, soil mass with the increase of number of freeze-thaw cyclic number, the cohesion C decreases. This paper analyzes the relationship between three factors which are temperature, moisture content and freeze-thaw cyclic number and the base tilt factor, it is concluded that a method to determine the base tilt factor of frozen-thaw soil. Using Terzaghi's formula of the limit equilibrium theory,the linear relationship between soil moisture at different temperatures and base tilt factor is established. Analysis the freeze and thaw temperatures, a method to determine the
This paper researches on the central south district in extreme snow disaster period, to properly determine the transmission of Kentucky foundation bearing capacity has certain practical significance.
引文
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[2]龚晓南.高等土力学[M].杭州:浙江大学出版社,1998.
[3]陈仲颐,周景星,王洪瑾.土力学[M].北京:清华大学出版社,1994.
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[5]刘昌辉,时红莲.基础工程学[M].武汉:中国地质大学出版社,2005.
[6]陈肖柏,刘建坤,刘鸿绪,王雅卿.土的冻结作用与地基[M].北京:科学出版社,2006.
[7]罗小刚,陈湘生,吴成义.冻融对土工参数影响的试验研究[J].建井技术,2000,25(2):24-26.
[8] Othman Majdi A, Benson Craig H. Effect of freeze-thaw on the hydraulic conductivity and morphology of compacted clay [J]. Canadian Geotechnical Journal, 1993, 30(2):236-246.
[9] Viklander Peter. Permeability and volume changes in till due to cyclic freeze and thaw [J]. Canadian Geotechnical Journal, 1998, 35(3): 471-477.
[10] Boynton S S, Daniel D E. Hydraulic conductivity tests on compacted clay [J]. ASCE Journal of geotechnical engineering, 1985, 116(10):1549-1567.
[11] Eigenbrod K D. Effects of cyclic freezing and thawing on volume changes and permeabilities of soft fine-grained soils[J]. Canadian Geotechnical Journal, 1996, 33(4): 529-537.
[12] Yong R N, Boonsinsuk P, Yin CW P. Alternation of soil behavior after cyclic freezing and thawing [A]. In: Proceedings of 4th International Symposium on Ground Freezing [C]. Rotterdam, the Netherlands: A. A. Balkema, 1985. 187-195.
[13]齐吉琳,程国栋, P.A.Vermeer.冻融作用对土工程性质影响的研究现状[J].地球科学进展,2005,20(5):887-892.
[14]齐吉琳,张建明,朱元林.冻融作用对土结构性影响的土力学意义[J].岩石力学与工程学报,2003,22(增2):2690-2694.
[15] Chamberlain Edwin J, Gow Anthony J. Effect of freezing and thawing on the permeability and structure of soils [J]. Engineering Geology, 1979, 13(1-4): 73-92.
[16] Konrad J. M. Physical processes during freeze-thaw cycles in clayey silts [J]. Cold Regions Science and Technology, 1989, 16(3):291-303.
[17] Taylor G S ,Luthin J N. A model for coupled heat and moisture transfer during soil freezing[J].Can Geotech J ,1978,15:548.
[18]毛然,王翠英.中南地区冻土抗剪强度因素的研究[J].安全与环境工程,2010,17(5):102-105.
[19]? ?马永芹.人工冻结法的理论与施工技术[M].北京:人民交通出版社,2007.
[20]王永忠,刘雄军,艾传井等.南方短时冻土抗剪强度指标c、φ值的试验研究[J].武汉大学学报(工学版),2010,43(2):198-202.
[21]刑静忠,王永岗.有限元基础与ANSYS入门[M].北京:机械工业出版社,2005.
[22]唐辉明,晏鄂川,胡新丽.工程地质数值模拟的理论与方法[M].武汉:中国地质大学出版社,2001.
[23]郝文化.Ansys土木工程应用实例[M].北京:中国水利水电出版社,2005.
[24]崔可锐,管政亭,赵川.淮南刘庄煤矿人工冻融土地基温度场数值模拟[A].加强地质工作,促进社会经济和谐发展——2007年华东六省一市地学科技论坛论文集[C],2007,349-352.
[25]桥曲甲线覆冰改造设计监理工作总结.鲤鱼江电厂～韶关(曲江)500kV送电线路工程.湖北中南电力工程建设监理有限责任公司,2008,5.
[26]陈勇.山东高速公路路基地基承载力评价方法研究.硕士学位论文,2005.
[27]马世敏.冻土抗剪强度实验研究[A].青藏冻土研究论论文集[C]:北京:科学出版社,1983:106-111.
[28]李广信.高等土力学[M].北京:清华大学出版社,2004.
[29]谢康和,周健.岩土工程有限元分析理论与应用[M].北京:科学出版社,2002.
[30] Miller R D. Frost heaving in non-colloidal soils [A]. The Third Int. Conf. on Permafrost [C]. Edmonton: National Research Council of Canada, 1978.708-713.
[31] Fukuda M. The pore water pressure profile in porous rocks during freezing [A]. 4th Int. Conf. on Permafrost [C], Fairbanks, Alaska: USA National Academy Press, Washington, D. C. 1983.322-326.
[32] Horiguchi K. An osmotic model for soil freezing [J]. Cold Reg. Sci. Technol. 1987, 14: 13-22.
[33]王大纯,张人权等.水文地质学基础[M].北京:地质出版社,1995.
[34]李同林,殷绥域.弹塑性力学[M].武汉:中国地质大学出版社,2006.
[35]赵明华,俞晓等.土力学与基础工程[M] .武汉:武汉理工大学出版社,2000.7
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[38]徐学祖.冻土物理学.科学出版社,2001.
[39]朱元林.冻土的弹性变形及压缩变形[J]冰川冻土.1982.
[40]陈希哲.土力学地基基础[M]北京:清华大学出版社,1998.
[41]林在贯.高大钊.岩土工程手册[M]北京:中国建筑工业出版社,1994.
[42] GB/T50123-1999.土Z试验方法标准[M].北京:中国计划出版社,1999.
[43]汪仁和,张世银,秦国秀.冻融土工程特性的试验研究.淮南工业学院学报.2001,21(4):35-37.
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[2]龚晓南.高等土力学[M].杭州:浙江大学出版社,1998.
[3]陈仲颐,周景星,王洪瑾.土力学[M].北京:清华大学出版社,1994.
[4]中华人民共和国建设部.建筑地基基础设计规范(GB50007-2002)[S].北京:中国建筑工业出版社,2002,20-21.
[5]刘昌辉,时红莲.基础工程学[M].武汉:中国地质大学出版社,2005.
[6]陈肖柏,刘建坤,刘鸿绪,王雅卿.土的冻结作用与地基[M].北京:科学出版社,2006.
[7]罗小刚,陈湘生,吴成义.冻融对土工参数影响的试验研究[J].建井技术,2000,25(2):24-26.
[8] Othman Majdi A, Benson Craig H. Effect of freeze-thaw on the hydraulic conductivity and morphology of compacted clay [J]. Canadian Geotechnical Journal, 1993, 30(2):236-246.
[9] Viklander Peter. Permeability and volume changes in till due to cyclic freeze and thaw [J]. Canadian Geotechnical Journal, 1998, 35(3): 471-477.
[10] Boynton S S, Daniel D E. Hydraulic conductivity tests on compacted clay [J]. ASCE Journal of geotechnical engineering, 1985, 116(10):1549-1567.
[11] Eigenbrod K D. Effects of cyclic freezing and thawing on volume changes and permeabilities of soft fine-grained soils[J]. Canadian Geotechnical Journal, 1996, 33(4): 529-537.
[12] Yong R N, Boonsinsuk P, Yin CW P. Alternation of soil behavior after cyclic freezing and thawing [A]. In: Proceedings of 4th International Symposium on Ground Freezing [C]. Rotterdam, the Netherlands: A. A. Balkema, 1985. 187-195.
[13]齐吉琳,程国栋, P.A.Vermeer.冻融作用对土工程性质影响的研究现状[J].地球科学进展,2005,20(5):887-892.
[14]齐吉琳,张建明,朱元林.冻融作用对土结构性影响的土力学意义[J].岩石力学与工程学报,2003,22(增2):2690-2694.
[15] Chamberlain Edwin J, Gow Anthony J. Effect of freezing and thawing on the permeability and structure of soils [J]. Engineering Geology, 1979, 13(1-4): 73-92.
[16] Konrad J. M. Physical processes during freeze-thaw cycles in clayey silts [J]. Cold Regions Science and Technology, 1989, 16(3):291-303.
[17] Taylor G S ,Luthin J N. A model for coupled heat and moisture transfer during soil freezing[J].Can Geotech J ,1978,15:548.
[18]毛然,王翠英.中南地区冻土抗剪强度因素的研究[J].安全与环境工程,2010,17(5):102-105.
[19]? ?马永芹.人工冻结法的理论与施工技术[M].北京:人民交通出版社,2007.
[20]王永忠,刘雄军,艾传井等.南方短时冻土抗剪强度指标c、φ值的试验研究[J].武汉大学学报(工学版),2010,43(2):198-202.
[21]刑静忠,王永岗.有限元基础与ANSYS入门[M].北京:机械工业出版社,2005.
[22]唐辉明,晏鄂川,胡新丽.工程地质数值模拟的理论与方法[M].武汉:中国地质大学出版社,2001.
[23]郝文化.Ansys土木工程应用实例[M].北京:中国水利水电出版社,2005.
[24]崔可锐,管政亭,赵川.淮南刘庄煤矿人工冻融土地基温度场数值模拟[A].加强地质工作,促进社会经济和谐发展——2007年华东六省一市地学科技论坛论文集[C],2007,349-352.
[25]桥曲甲线覆冰改造设计监理工作总结.鲤鱼江电厂～韶关(曲江)500kV送电线路工程.湖北中南电力工程建设监理有限责任公司,2008,5.
[26]陈勇.山东高速公路路基地基承载力评价方法研究.硕士学位论文,2005.
[27]马世敏.冻土抗剪强度实验研究[A].青藏冻土研究论论文集[C]:北京:科学出版社,1983:106-111.
[28]李广信.高等土力学[M].北京:清华大学出版社,2004.
[29]谢康和,周健.岩土工程有限元分析理论与应用[M].北京:科学出版社,2002.
[30] Miller R D. Frost heaving in non-colloidal soils [A]. The Third Int. Conf. on Permafrost [C]. Edmonton: National Research Council of Canada, 1978.708-713.
[31] Fukuda M. The pore water pressure profile in porous rocks during freezing [A]. 4th Int. Conf. on Permafrost [C], Fairbanks, Alaska: USA National Academy Press, Washington, D. C. 1983.322-326.
[32] Horiguchi K. An osmotic model for soil freezing [J]. Cold Reg. Sci. Technol. 1987, 14: 13-22.
[33]王大纯,张人权等.水文地质学基础[M].北京:地质出版社,1995.
[34]李同林,殷绥域.弹塑性力学[M].武汉:中国地质大学出版社,2006.
[35]赵明华,俞晓等.土力学与基础工程[M] .武汉:武汉理工大学出版社,2000.7
[36]崔托维奇H A.冻土力学[M].张长庆,朱元林译.北京:科学出版社,1985.19
[37]童长江,管枫年.土的冻胀与建筑物冻害防治.水利电力出版社.1985
[38]徐学祖.冻土物理学.科学出版社,2001.
[39]朱元林.冻土的弹性变形及压缩变形[J]冰川冻土.1982.
[40]陈希哲.土力学地基基础[M]北京:清华大学出版社,1998.
[41]林在贯.高大钊.岩土工程手册[M]北京:中国建筑工业出版社,1994.
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