例一某计算行车速度为60km/n的三级公路,交点桩号为K0+518.66,转角=18°18′36″,圆曲线半径R=300m,缓和曲线长LS=50m,试计算平曲线测设元素和主点里程桩号,并测设主点桩。解:1.计算缓和曲线常数:926443002180501802RLS35.030024502422RLpS(m)253002405025024022323RLLqSS(m)65.49300405050402323RLLxSSh(m)39.1300650622RlySh(m)34.33300126050115032126011322323RLLtSSd(m)68.1630012605050311260312323RLLtSSk(m)2.测设元素计算40.73252638118)35.0300(2)(tgqtgpRTh(m)87.14550180638118300180ShLRL(m)22.43002638118sec)35.0300(2sec)(RpREh(m)Dh=2Th-Lh=2×73.40-145.87=0.93(m)3.主点里程桩号计算JDK0+518.66-)Th73.40ZHK0+445.26+)LS50HYK0+495.26+)LY45.87YHK0+541.13+)LS50HZK0+591.13—)Lh/2145.87/2QZK0+518.95+)Dh/20.46JDK0+518.66(校核无误)4.主点桩测设(1)由JD沿前后切线方向分别量取Th=73.40m得ZH和HZ点桩位。(2)由JD沿分角线方向量取Eh=4.22m得QZ点桩位。(3)根据xh=49.65m,yh=1.39m,分别以ZH和HZ点为原点,用切线支距法定出HY和HY点的位置。例二根据例一的计算结果,计算用切线支距法测设K0+460、K0+500桩的测设数据。解:1.K0+460桩位于ZH~HY段,用公式(10-29)计算:l=460-445.26=14.74(m)74.14503004074.1474.1440225225SLRllx(m)03.050300674.14633SRLly(m)2.K0+500桩位于HY~QZ段,可用两种方法测设以ZH为坐标原点、ZH的切线为x轴建立坐标系时,用公式(10-30)计算:l=500-495.26+50/2=29.74(m)69.542518030074.29sin300180sinqRlRx(m)82.135.018030074.29cos1300180cos1pRlRy(m)以HY为坐标原点、HY的切线为x轴建立坐标系时,用公式(10-31)计算l=500-495.26=4.47(m)47.418030047.4sin300180sinRlRx(m)03.018030047.4cos1300180cos1RlRy(m)例三根据例一的计算结果,计算用偏角法测设K0+460、K0+500桩的测设数据。解:1.K0+460桩位于ZH~HY段,仪器置于ZH点测设,用公式(10-35)计算l=460-445.26=14.74(m)8180018050300674.1418062SRLlC≈l=14.74(m)2.K0+500桩位于主曲线段,仪器置于HY点测设l=500-495.26=4.74(m)90720180300274.41802Rl74.4)180300274.4sin(3002)1802sin(2RlRC(m)