中文摘要：

实测数据统计结果表明,沉管隧道施工期间的沉降占到总沉降的50%以上,而施工期间沉降主要由基础层压缩引起。以舟山沈家门港海底沉管隧道为原型,取纵向30 m建立1∶10缩尺寸模型,试验重点模拟海水环境下注砂基础层形成过程,并研究其在不同回淤条件下的整体压缩过程,评估回淤对压缩的影响。研究结果表明:无回淤条件下砂石基础层整体压缩模量为3.41 MPa,表明沉管隧道基础层的压缩性能较差;夹杂不同浓度的回淤层后,基础层整体压缩模量在1.54~3.89 MPa区间,集中在2.34 MPa附近,约为无回淤条件的0.69倍;回淤起到类似润滑剂的作用,增加了砂石的交错重叠量和垫层整体的塑性,会延长压缩稳定时间,增加基础层的压缩量,放大压缩区域的不均匀性。

英文摘要：

The measured statistical results show that the settlement of immersed tube tunnels during construction accounts for more than 50% of the total one and is mainly caused by compression of the base layer. Based on the prototype of Shenjiamen Port immersed tube tunnel in Zhoushan, a 1:10 scale shrinkage model is established for the longitudinal length of 30 m focusing on the formation process of sand base layer in marine environment to study its compression process under different deposition conditions and to assess the impact of back silting. The results shows under no silt gravel, the compressibility modulus of the overall base layer is 3.41 MPa, indicatings the poor compression performance of base layer. Under different concentrations of back silting, the compressibility modulus of the base layer ranges from 1.54 to 3.89 MPa, mainly about 2.34 MPa, about 0.69 times that without back silting. The silting acts like lubricant which increases the interleave of sand and gravel, extends the compression settling time, increases the compression amount of base layer and enlarges the regional inhomogeneity.