安嵩线草海段泥炭质土的特征及性质

Features and properties of peaty soil in Caohai section of Anning-Sonming line

规划中的安嵩线草海段拟采用盾构隧道工程下穿通过,泥炭质土是该段的主要工程地质问题。对安嵩线草海段泥炭质土的沉积环境、分布、特征及一般物理力学指标等进行了研究,并重点对第二层泥炭质土的特殊指标进行了分析。第二层泥炭质土具有压缩性大、固结度差、抗剪强度及无侧限抗压强度偏高、灵敏度低、动强度低、动剪切模量比偏大、阻尼比偏小等特点,对盾构隧道工程影响较大,易引起较大的沉降及不均匀沉降、抗震性能差,因此方案及措施的选择应充分考虑泥炭质土的特殊性。

As for the planning Caohai section of Anning-Songming line which adopts shield tunnel project, the peaty soil is the main engineering geological problem. The sedimentary environments, distribution, characteristics and general physical and mechanical indices of the peaty soil are studied, and the special in dices of the second layer of peaty soil are analyzed. The second layer of peaty soil with large compressibility, low degree of consolidation, high shear strength and unconfined compressive strength, low sensitivity, low dynamic strength, large dynamic shear modulus ratio and small damping ratio has great influence on the shield tunnel project. Large settlement and differential settlement are easily caused, and the seismic performance is poor. Accordingly, the test schemes and measures should fully consider the particularity of the peaty soil.