黄河三角洲地下咸水对水泥土搅拌桩复合地基承载特性的影响研究

A Study on Influence of Salt Groundwater in Yellow River Delta on Bearing Behavior of Soil-Cement Pile Composite Foundation

为了研究黄河三角洲地区地下咸水对水泥土搅拌桩复合地基承载特性的影响,对典型地段地下土和水进行了勘察分析,对含盐水泥土的劣化进行了试验研究,并基于Biot固结理论对含盐水泥土复合地基进行了固结分析。研究发现,地下水呈酸性,阳离子主要为K+、Na+,阴离子主要为Cl-、SO24-;盐对水泥土有较强的腐蚀作用,90d龄期含盐水泥土抗压强度比淡水环境降低18.5%,180d的降低了21.6%;水泥土劣化对超静孔隙水压力影响不明显;水泥土劣化使桩轴向应力水平提高15%以上;水泥土劣化使水平位移及竖向沉降都有所增大。这表明咸水腐蚀对水泥土复合地基承载性能的影响不可忽略,在设计和施工中应充分重视,需采取耐久性措施以保证道路服役期的安全运营。

In order to study the influence of soil-cement degradation due to salt water in the Yellow River delta on loading and deformation characteristics of mixed pile composite foundation,surveys and analyses are conducted to unveil the properties of groundwater and soil using representative test,and experiments are carried out to study degradation of saliferous soil-cement.With the influence of excess pore water pressure concerned,a Mohr-Coulomb model is adopted based on Biot consolidation theory to simulate the consolidation of soil-cement pile foundation.Research found that groundwater showed acidic property,and cationic mainly included K＋、Na＋,anionic mainly included Cl-、SO2-4.Salt water is corrosive significantly to soil-cement,the compressive strength of saliferous soil-cement is 18.5% lower when 90 days and it came to 21.6% lower after 180 days.The degradation of soil-cement had impressive influence on pile axial stress level and made it rise more than 15%.The horizontal displacement and vertical settlement had increased due to the degradation while the excess pore water pressure kept the same with the ordinary soil-cement.It shows that the influence of salt water corrosion on bearing characteristics of soil-cement pile foundation must be taken into consideration.Durability measures must be taken to prevent subsequent road damage from happening.