lBD?24?(109.610?68.506)?24?19.6?10?6?(10?15)73000虚数 ? ?32?320.402?10?0.478?10????lCD?24?(109.610?68.506)?24?19.6?10?6?(?5?15)73000虚数? ?32?320.427?10?0.478?10
????表2-3 临界档距判别
A lAB?324.39m B lBC?虚数 C lCD?虚数 lAC?159.09m lAD?虚数 lBD?虚数 因为A、B、C栏均存在虚数，所以全线收年平均气温控制。见下图：
由上图可知，全线受D条件控制，控制应力?m?68.506N/mm2。 2.4 导线应力计算（以导线在最高气温下应力的分析计算为例）
Egnl2Egml213.5A?aE(t?t) B??m? A????C nm232424?mB22当B?0时C?1,B?0时C??1。如果??1有???rcch??ln(???2?1),
?n?
B3(2ch?3??C)，ch?e3?e?32??3，如果??1有???rccos?，?n?B (2cos?C)，
33?计算各种气象条件下的应力。
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（1） 求最高气温时导线应力曲线，此时，65.51m以下为最低气温控制，控制应力为
?m?109.61N/mm2 。65.51m以上为年平均气温控制，控制应力为?m?68.506N/mm2最高气温为待求条件。 当l0?50m时，则：
Egnl273000?(32.773?10?3)2?502A???8167.41
24242Egml2B??m??aE(tn?tm)224?m?109.61?73000?(32.773?10)?50?19.6?10?6?73000?(40?10)?66.01?0224?109.61?3222
??13.5AB3?C?13.5?8167.466.013?1?1.38?1 ，
???rcch??ln(???2?1)?ln(1.38?1.382?1)?0.85 ?n?67.78MPa查表2-1-1得：f=0.326m 当l0?100m时，则：
Egnl273000?(32.773?10?3)2?1002A???32669.6
24242Egml2B??m??aE(tn?tm)224?m?68.506?73000?(32.77?10)?100?19.6?10?6?73000?(40?10)?18.62?0224?68.506?3222
??13.5AB3?C?13.5?32669.618.623?1?69.31?1
2???rcch??ln(???2?1)?ln(69.31?69.31?1)?4.93
?n?39.53MPa查表2-1-1得：f=1.036m
当l0?150m时，则
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Egnl273000?(32.773?10?3)2?1502 A???73506.6324242Egml2B??m??aE(tn?tm)224?m?68.506?73000?(32.773?10)?150?19.6?10?6?73000?(40?10)?9.92?0224?68.506?3222
??13.5AB3?C?13.5?73506.63?1?1017.79?1 ???rcch??arcch1017.79?7.62 39.92?n?45.47??a
查表2-1-1得：f=2.027m 当l0?200m时，则：
Egnl273000?(32.773?10?3)2?2002 A???130678.4624242Egml2B??m??aE(tn?tm)224?m?68.506?73000?(32.773?10)?200?6?19.6?10?73000?(40?10)?-2.26 <0224?68.506?3222
??13.5AB3?C?13.5?130678.460.98)?12.63 ?1?152229?1 ???rccos??arccos(32.26?n?50.003??a
查表2-1-1得：f=3.277m 当l0?250m时，则：
Egnl273000?(32.773?10?3)2?2502 A???204185.0924242Egml2B??m??aE(tn?tm)224?m?68.506?73000?(32.773?10)?250?19.6?10?6?73000?(40?10)??17.93?0224?68.506?3222
??477.55?1 ???rcch??6.86
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?n?53.48??a
查表2-1-1得：f=4.788m 当l0?300m时，则：
Egnl273000?(32.773?10?3)2?3002 A???294026.5324242Egml2B??m??aE(tn?tm)224?m?68.506?73000?(32.773?10)?300?19.6?10?6?73000?(40?10)??37.07?0224?68.506?3222
??13.5AB3?C?76.93?1
???rcch??5.04
?n?B3(2ch?3?C)?56.16??a
查表2-1-1得：f=6.565m 当l0?350m时，则：
Egnl273000?(32.773?10?3)2?3502 A???400202.7824242Egml2B??m??aE(tn?tm)224?m?68.506?73000?(32.773?10)?350?19.6?10?6?73000?(40?10)??59.69?0224?68.506?3222
??13.5AB3?C?24.4?1
???rcch??3.89
?n?B3(2ch?3?C)?58.25??a
查表2-1-1得f=8.615m 当l0?400m时，则：
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Egnl273000?(32.773?10?3)2?4002 A???522713.8424242Egml2B??m??aE(tn?tm)224?m?68.506?73000?(32.773?10)?400?19.6?10?6?73000?(40?10)??85.8?0224?68.506?3222
??13.5AB3?C?10.17?1
???rccos??3.01
?n?B(2cos?C)?59.9??a 33?查表2-1-1得：f=10.943m 当l0?450m时，则：
Egnl273000?(32.773?10?3)2?4502 A???661559.724242Egml2B??m??aE(tn?tm)224?m?68.506?73000?(32.773?10)?350?19.6?10?6?73000?(40?10)??115.38?0224?68.506?3222
??13.5AB3?C?4.81?1
???rcch??2.25
?n?B3(2ch?3?C)?61.207??a
查表2-1-1得：f=13.553m 当l0?500m时，则：
Egnl273000?(32.773?10?3)2?5002 A???816740.7324242 16