在灌涝区修建小型交通桥往往会碰上流沙很厚的地质条件。在这种情况下修筑桥基由于基坑深、开挖面小,且地下水位高、水量大,而无法采用开沟排水或沉箱戽水等常规的处理方法。这时必须增加隔离基坑内外流沙联系的设施,才能挖沙建基。对此,黑龙江省北安市水利技术人员过去曾采用现场浇注与下沉大径(φ=200厘米)水泥管的方 The construction of small traffic bridges in irrigation districts is often met with very thick geological conditions. In this case, due to the deep foundation pit, small excavation surface, and high groundwater level and large amount of water, it is impossible to adopt conventional treatment methods such as trench drainage or caisson and dredge. At this time, it is necessary to increase the facilities that separate the sand from the inside and outside of the foundation pit in order to excavate the sand. In this regard, the water conservancy technicians of Bei’an City, Heilongjiang Province used the method of pouring and sinking large-diameter (φ=200 cm) cement pipes on site.