顶管隧道工程触变泥浆性能试验及减阻技术研究

文章依托郑州市红专路下穿中州大道顶管隧道工程,通过室内泥浆性能试验,研究了膨润土、CMC、纯碱和PHP四种材料含量的改变对触变泥浆性能的影响规律,并由此确定了触变泥浆的配合比。然后,结合现场施工情况,研究了触变泥浆制备、注浆设备选型、注浆参数设计、梅花形注浆孔位布置、同步注浆和二次注浆施工以及管节表面涂蜡等减阻技术。最后,通过土压力理论计算和现场实测得出结论:采取减阻技术措施后,机动车大断面隧道的最大顶推力和平均摩阻系数分别减小了56.3%和62.3%;非机动车隧道的最大顶推力和平均摩阻系数分别减小了56.7%和60.9%,减阻技术应用效果良好。

Mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions

To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elastic modulus, the mass variation,and the compressive strength of cement mortar increase first, and then decrease with increasing erosion time in sodium sulfate and sodium chloride solutions. The relative dynamic elastic moduli and the compressive strengths of cement mortars with water/cement ratios of 0.55 and 0.65 in sodium sulfate solution are lower than those in sodium chloride solution with the same concentration at the420 th day of immersion. The compressive strength of cement mortar with water/cement ratio of 0.65 is more sensitive to strain rate than that with water/cement ratio of 0.55. In addition, the strain-rate sensitivity of compressive strength of cement mortar will increase under attacks of sodium sulfate or sodium chloride solution.