根據(jù)沉降隨荷載的變化特征確定極限承載力:對(duì)于陡降型Q-s曲線,取發(fā)生明顯陡降起始點(diǎn)的荷載為極限荷載;根據(jù)沉降量確定極限承載力:對(duì)于緩變型Q-s曲線,一般可取s=40mm對(duì)應(yīng)的荷載值;對(duì)于大直徑可取s=0.03~0.06D(D為樁端直徑,大樁徑取低值,小樁徑取高值)所對(duì)應(yīng)的荷載值;對(duì)于細(xì)長(zhǎng)樁(l/d>80)可取s=60~80mm對(duì)應(yīng)的荷載值作為極限荷載;