摘要
本研究為探討群樁承受軸向力之載重變形行為，求出案例之載重與變形理論值，其結果與案例測量值比對，並以合理假設做修正◦文中介紹Randolph基樁軸向載重之變形分析及群樁軸向載重變形分析，並利用以此理論為基礎發展之PileGPw軟體做計算，求取群樁中各單樁之樁頭、樁身及樁底載重◦已知樁身總載重，可假設各種樁身剪力分佈，由此計算樁身載重分佈，與案例測量值比對，並利用單樁極限承載力及群樁效應修正◦
研究結果顯示，將樁上半部剪力假設隨身度呈線性增加，下半部皆為定值，理論值與實際值相當吻合◦理論分析時，假設樁帽為剛性，依照每根樁的位置不同，所承受之載重亦不同；角落樁承受之載重會大於群樁載重除以樁數之平均值，而邊緣樁及中央樁皆小於平均值，但邊緣樁最接近平均值◦實際情況，樁帽並非完全剛性，案例中群樁之測量值與理論值在低載重時很接近；但在高載重時，測量值與理論值差距變大，特別是在中央樁的部分◦利用單樁極限承載力及群樁效應修正得到之結果與測量值十分近似◦

SUMMARY
This paper described Randolph and Wroth (1978, 1979) article about deformation of vertically loaded piles. The results showed that the pile will carry upper half of the shear force increases linearly with depth, the lower half are constant. The theoretical value and the measured value is quite consistent. For rigid pile caps, the load of corner pile will be greater than the average value of total load divided by the number of piles. Central pile and edge piles are less than the average value. The edge piles are the closest to the actual situation in the pile cap. In actual situation, the measured value and the theoretical value of the group is well agreement on the pile at low loading condition. However, at high loading condition, there is a gap between the measured values and the theoretical value. The results of theoretical and the measured values will be very similar after the value corrected with ultimate bearing capacity and pile groups effect.

Key Words: pile groups, vertical deformation, load distribution, t-z curve

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