不规则场地下基坑围护体系优化设计

Optimization Design of Foundation Pit Enclosure System at Irregular Site

随着城镇建设的不断推进而产生不规则的场地,在基坑设计和施工考虑上都要比规则场地复杂,结合某不规则基坑工程实例,在考虑工程地理位置、土质条件、基坑开挖深度和周围环境条件等因素后,采用上部放坡开挖、下部SMW工法桩加内支撑,局部被动区搅拌桩加固方案,使工程在质量、安全、环境、工期及经济效益等多方面达到预期效果。在安全方面,运用理正和PLAXIS有限元软件进行基坑变形计算,分析得到:当场地呈不规则形时,此方案较其他方案相比更经济安全;理正和PLAXIS模拟基坑变形的趋势大致相同,侧向位移最大值发生在基坑底部;地表沉降随桩后距离先增后减,其值均在设计安全范围内,可为杭州同类基坑提供一定的参考价值。

With the rapid development of the urban construction, the irregular space have been appeared, which is more complex in design and construction of foundation pit considering than the regular ones. Combined with an irregular foundation pit engineering as an example, we used the upper slope excavation, lower SMW pile plus strut, local passive zone mixing pile reinforcement scheme under considering the engineering geological location, soil condition, foundation pit excavation depth and the surrounding environment condition factors, to achieve the aims in terms of quality, safety, environment, construction period and economic aspects of the desired effect.In terms of safty,we applied theory with finite element software PLAXIS and Lizheng to calculate the foundation’s deformation. Results show that on the spot to the irregular shape, this plan is more economic than other security. PLAXIS and Lizheng simulation of the deformation trend is roughly same. Maximum lateral displacement occurs in the bottom of the foundation pit. With the pile’s distance increasing, ground surface settlement increased at first and then decreased. The value of number was within the scope of the design safety. This theory can have certain reference value to the similar foundation pit of Hangzhou.