围护桩水平位移反分析弯矩及桩侧土压力  

Back analysis of bending moment and earth pressure based on horizontal displacement of retaining pile

作　　者：魏焕卫[1] 孙元硕 Wei Huanwei;Sun Yuanshuo(College of Civil Engineering,Shandong Jianzhu University,Jinan 250101,China)

机构地区：[1]山东建筑大学土木工程学院,济南250101

出　　处：《工程勘察》2022年第6期1-7,25,共8页Geotechnical Investigation & Surveying

基　　金：国家自然科学基金(41272281)。

摘　　要：为探讨深基坑排桩支护的内力分布与作用于支护结构上的土压力分布状况,基于桩体深层水平位移监测数据对桩体内力及桩侧土压力进行了反分析研究。在三次样条法的基础上,对五次样条函数进行推理,建立桩体深层水平位移与桩弯矩和桩侧土压力的函数关系式,结合某工程实测数据,得出位移反分析后的桩体弯矩与桩侧土压力,最后将理论值与实测值进行了对比。研究结果表明,弯矩反演结果与实测弯矩值吻合程度较好;在开挖面以上,围护结构位移较小时,位移反分析得到的土压力大于朗肯主动压力,随着开挖变形增大,土体产生应力松弛,位移反分析得到的主动区土压力小于朗肯主动土压力。在开挖面以下,土压力的分布形式接近于规范提出的弹性法基坑内侧分布土反力与主动土压力差值。In order to explore the internal force distribution of pile retaining structure in deep excavation and the distribution of soil pressure acting on the retaining structure,the pile internal force and the soil pressure is back analyzed based on the monitoring data of the horizontal displacement of the pile shaft.On the basis of the cubic spline method,the quintic spline function is inferred,and the functional relationship between the deep horizontal displacement and bending moment,the soil pressure of the pile shaft is established.According to the monitoring data of a project,the back analysis result of pile shaft bending moment and soil pressure are obtained,and then compared with the measured value.The comparison result shows that the bending moment inversion result is consistent with the measured bending moment value;when the displacement of the retaining structure above the excavation face is small,the earth pressure obtained from the back analysis is greater than the active earth pressure of Rankine.With the increase of excavation deformotion,the stress relaxation occurs in the soil,and the active earth pressure obtained by the back analysis is less than the active earth pressure of Rankine.The distribution pattern of earth pressure below the excavation face is close to the difference between the earth reaction force in the inner surface and active earth pressure calculated according to code.

关 键 词：深层水平位移 反分析 五次样条法 弯矩 土压力 

分 类 号：TU443[建筑科学—岩土工程]