摘要
尝试提出群桩沉降计算的试桩曲线Q-S法,将群桩在准永久组合下单桩平均荷载对应的沉降划分为线弹性部分和非线弹性部分,引入了群桩沉降比来反映完全弹性部分的相互作用,同时引入了弹性程度发挥系数来反映非线弹性部分沉降的相互作用。通过2个工程实例的计算分析讨论了群桩沉降比、在单桩平均荷载下对应沉降中线弹性部分和非线弹性部分所占的比例、以及弹性程度发挥系数等参量对于试桩曲线法的影响。文中结合弹性层状理论的传递矩阵和层状土单桩分析方法,利用矩阵位移法推导了层状土中群桩的弹性位移解刚度矩阵和求解公式。计算表明,层状土中群桩解答与简单处理为均匀土中的解答对群桩沉降比计算结果影响很大,差距近达40%。最后通过全国各地区11个桩基工程的实例分析,将试桩曲线法计算结果与实测值以及其他分析方法的计算结果进行了比较,表明由于试桩曲线法包含了桩基工程的实际特性,因而具有较强的地区适用性和相对较高的分析精度。
The calculation method of pile group settlement applied with static load test results is proposed in this paper, which separates settlement of single pile under quasi-permanent combination of load into two parts, one is linear elastic part, the other is nonlinear elastic part. Settlement ratio is adopted to analyze the interaction of linear elastic displacement in pile group. And elastic development degree ratio is used to reflect the interaction effect in nonlinear elastic displacement of pile group. Parametric analysis of two pile engineering examples shows that pile settlement ratio is the most influential parameter, next came proportion between linear and nonlinear elastic displacement of single pile, and elastic development degree ratio has the least influence on pile group settlement calculation with pile static load test curve. Soil is usually layered distribution especially in soft soil region. On the basis of it, displacement solution of pile settlement in layered soil are derived with matrix displacement methods based on transfer matrix and analysis results of single pile in layered soil. Then parametric analysis is conducted for pile group in double-layer soil arid three-layer soil with representative soil characteristic. For two pile group settlement analysis theory, that is displacement solution for layered soil given above and elastic solution method with soil modulus approximate treatment, pile group settlement ratio＇s difference is very significant, which can be seen that differential value reachs about 40%. Lastly more than ten pile engineering examples are analyzed with pile group settlement method based on static load test curve. Analysis results show the method is reasonable, more accurate and has strong regional applicability.
出处
《结构工程师》
2008年第5期77-88,125,共13页
Structural Engineers
关键词
试桩曲线
沉降比
分层土
弹性程度发挥系数
static load test curve, settlement ratio, layered soil, elastic development degree ratio
