摘要
以工程建设项目为背景,探究在实际工程中采用磷酸溶液代替硫酸溶液对水玻璃进行化学改性后作为注浆材料对地下松散砂土层加固的可行性和有效性。通过对溶液物理性能研究的室内试验,确定适合采用的溶液配合比,然后进行无侧限抗压强度试验和直接剪切试验,以此分析改性水玻璃溶液对砂土层的加固效果和加固机理。最后,采用Midas有限元软件建立地铁盾构开挖的三维数值模型,对地铁隧道开挖的安全性进行影响评估,根据数值模拟结果可以直观分析加固方法的有效性。试验结果表明:磷酸改性的水玻璃溶液对松散砂土具有明显加固作用,适合在实际工程中使用的溶液最优体积配合比为水∶磷酸∶水玻璃=13∶1∶3.3;根据模拟渗透试验可知,1m^(3)的浆液可固结砂土约4.75m^(3)。试样的抗剪强度参数值随溶液凝结硬化时间的增长呈线性变化,当溶液对砂土粘聚力和内摩擦的作用达到平衡时抗剪强度最大。
In the actual project,phosphoric acid solution is used instead of sulfuric acid solution to chemically modify sodium silicate to strengthen the underground loose sand layer.Based on grout physical properties,a suitable mix ratio is determined.The reinforcement effect and mechanism of modified sodium silicate solution on the sand layer are studied by using unconfined compressive strength tests and direct shear tests.Lastly,Midas finite element software is used to establish a three-dimensional numerical model of subway shield excavation.Based on the numerical simulation results,the reinforcement method's effectiveness can be intuitively analyzed.The testing results show that the phosphoric acid modified sodium silicate solution has an obvious strengthening effect on loose sand,and the optimal volume mix ratio suitable for practical engineering is water:phosphoric acid:sodium silicate=13:1:3.3.According to the simulated permeability tests,about 4.75m'sand can be consolidated by using lm grouting solutions.The shear strength of the samples varies linearly with time,and the shear strength reaches its maximum when the two effects of solution on sand's cohesion and internal friction angle reach a balance.
作者
褚峰
薛沛柯
张宏刚
陈挺
蔡青松
Chu Feng;Xue Peike;Zhang Honggang;Chen Ting;Cai Qingsong(School of Urban Planning and Municipal Engineering,Xi'an Polytechnic University,Xi'an 710048,China;China Coal Engineering Ecological Environment Technology Co.,Ltd,Beijing 100013,China;Airport Construction Engineering Co.Ltd,Tianjin 300456,China)
出处
《工程勘察》
2023年第12期1-7,共7页
Geotechnical Investigation & Surveying
基金
国家自然科学基金项目(52178355)
陕西省自然科学基础研究计划资助项目(2020JM-572)
西安市碑林区科技计划资助项目(GX2148)
。
关键词
改性水玻璃
磷酸
溶液配合比
应力—应变曲线
抗剪强度
modified sodium silicate
phosphoric acid
solution mixture ratio
stress-strain curve
