深大地连墙圆形基坑环向稳定性模型试验研究
打开文本图片集
中图分类号：TU753 文献标志码：A DOI： 10.15935/j.cnki.jggcs.20250410.001
AbstractThe circular foundation pit with underground continuous wallhas the characteristics of good spatial performance and it is more suitable for the foundation pit enclosure system of ultra-deep underground structures especially in the soft soil area.The deepand large circular foundation pit is mainly under circumaxial force.Due to the non-uniformity of geology，construction accuracyand load，the weak joint is under eccentric pressure.With the increase of depth and diameter，theproblemof circum-axial stability becomes more and more prominent. However，at present，the spatial instability patern and mechanism of the circular grounding wall are not clear，and the judgment of the circular grounding wall stability of the existing foundation pit design norms is not perfect.Therefore，this paper takes a circular grounding wallfoundation pit （diameter of about 92m ，depth of about 50m ）of a 25O OOO square LNG underground membrane tank as the prototype to carry out model tests. According to the similarity principle，the geometric similarity ratio of 1：50 （20 was set up，and 3 models with diferent framing，including "T" joint and circular steel ring beam were made， and 4 groups of load conditions were designed to study the circumferential stability of circular ground wal with different framing under uniform confining pressure and biased load.The results show that：1） the maximum load varies greatly in each working condition，and the failure modes include local buckling and T-joint failure; 2）The radial displacement at top is larger than that atbotom，trapezoidal load displacement is less than the partial load；3） The ring direction is compressive stress，and the vertical stress is trapezoidal confining pressure under internal pressure and external pull.Through the critical pressure analysis，the critical failure load of the test model was 3.99＼～8.31 times of the Mises formula value，while the Mises bearing capacity was stronger.4）The circumferential stability of circular foundation pit of deep underground continuous wall belongs to flexural strength failure and unstable failure.The test methods and conclusions in this paper have good engineering reference value for such problems.
KeywordsCircular foundation pit，circumferential stability，model test，critical load
0 引言
圆形基坑凭借其显著的空间效应和地下连续
墙（简称"地连墙"）的拱效应[1-3]，能充分发挥混凝土抗压性能，在深大地下工程中的应用日益广泛[45]，表1统计了国内外典型深大圆形基坑的应用案例。（剩余13355字）
