高速公路扩建工程高填方路基拓宽的原位监测与分析

拓宽高速公路对路基变形的控制标准高于一般新建高速公路。沪宁高速公路扩建工程部分填方路段拓宽路堤高达6．0m～9．0m，且地基中存在软弱夹层。经选取典型断面对拓宽路堤施工过程进行沉降和深层水平位移监测与分析，结果表明：施工过程中的沉降和位移速率均小于控制标准，路基未出现失稳迹象，采用的填土速率（≤10kPa／d）可行；路堤完工3个月后拓宽路基沉降已趋于稳定，工后差异沉降不超过0．2cm，均小手相应控制标准。

Study on Treatment Method and Characteristic of Typical Soft Clay Foundation at Shanghai-Nanjing Freeway Extension Engineering

The deformation control standard of widening expressway has a higher level than that of newly-built expressway. In Hu-Ning expressway widening project there are sections of embankment of 6.0- 9.0 m high with thin soft soil layer beneath shallow ground. Some typical sections were monitored and analyzedfor settlement and deep horizontal displacement during widening embankment eonstruction, the results indicates that： the rates of settlement and horizontal displacement were lower than the control standard, the roadbed had no failure symptom, so the adopted construction rate（≤10 kPa/d） was feasible. The average settlement rate of three months later than completion was not higher than 0. 5 mm/d, lower than the acceptance standard （ 〈0.1 mm/d） of embankment. The settlement prediction showed that the post-construction settlement of the monitoring section was not higher than 2.2 era, and post-construction differential settlement not higher than 0.2 cm, both lower than their control standard respectively.