中文摘要：

具有内支撑结构的围护系统在基坑边角处具有更大的系统刚度，使得基坑边角附近处土体的位移小于距离边角较远处土体的位移，即基坑的变形问题表现出空间特性。为了更好地研究L/He（L为沿基坑纵向方向上的距离；He为开挖深度）、开挖深度等因素对空间效应的影响，量测了两个狭长形地铁车站深基坑不同位置处土体的侧向位移、土体沉降等。通过对现场监测资料的分析发现，边角效应能够减小侧向位移的平面应变比，灌注桩围护结构、SMW工法桩围护结构和地下连续墙在边角附近处的平面应变比（PSR）分别为0.50、0.61和0.72。当平面应变比（PSR）接近于1.00时，对应的L/He值分别为2.50、6.00和4.00。随着L/He值的增大，土体的纵向最大沉降呈先增大后保持稳定的趋势。随开挖深度的增加，边角效应的影响范围呈增大的趋势。在基坑纵向沉降的空间效应中，灌注桩围护结构、SMW工法桩围护结构的土体最大沉降值达到稳定时对应的L/He值分别为2.50和5.20。土体沉降和侧向位移的空间效应有一定的相关性。

英文摘要：

Spatial effects of strutted retaining structure caused by the higher stiffness at the corners lead to smaller ground movements near the corners and larger ground movements toward the middle of the excavation wall. In order to analyze the effects of influential factors such as the value of L/He （L is the distance in the longitudinal direction; He is the excavation depth） and excavation depth on spatial effects, a series of a field monitoring exercise including lateral displacement and soil settlement are conducted at two similar subway station deep foundation pits. Field monitored data indicate that the strengthening corner effect can lead to a significant reduction in wall deflection and the plane strain ratio（PSR）. The plane strain ratio near the excavation corner is 0.50, 0.61, 0.72, respectively for the bored pile wall, soil mixing wall, diaphragm wall retaining structure. The corresponding value of L/He is 2.50, 6.00 and 4.00 when the plane strain ratio approaches to 1.00. Longitudinal maximum settlement increases first and holds steady with the increase of the value of L/He and the corner effect also increases with the increase of excavation depth. The corresponding value of L/He for the bored pile wall and soil mixing wall is 2.50 and 5.20, respectively, when the maximum settlement achieve stable value. The spatial effects of wall deflection are related to the surface settlement behind the retaining structure.