以成宜高速公路ZCB1标段为工程背景,采用FLAC3D有限差分软件建立相应路基模型,计算分析了地基土在固结与未固结两种工况下的路堤填筑稳定性,得出以下结论:①未固结软土天然强度薄弱,但经固结后强度满足一般路基设计需求;②地基土抗剪强度较低时,地表倾斜对地基土的位移影响更为明显.临界状态时,路基结构倾向于从薄弱一侧先发生破坏,另一侧保持相对稳定;③软土天然渗透系数较低,仅依靠堆载促进软土渗流固结,所需施工时间偏长,在工程中应结合工期和成本,合理选择地基处理方式.

In the booming field of nanotechnology, colloidal silica (CS) has been introduced for ground improvement and liquefaction mitigation. It possesses a great ability to restrain pore pressure generation during seismic events by using an innovative stabilization technique, with the advantages of being a cost-effective, low disturbance, and environmentally friendly method. This paper firstly introduces molecular structures and some physical properties of CS, which are of great importance in the practical application of CS. Then, evidence that can justify the feasibility of CS transport in loose sand layers is demonstrated, summarizing the crucial factors that determine the rate of CS delivery. Thereafter, four chemical and physical methods that can examine the grouting quality are summed and appraised. Silica content and chloride ion concentration are two effective indicators recommended in this paper to judge CS converge. Finally, the evidence from the elemental tests, model tests, and field tests is reviewed in order to demonstrate CS's ability to inhibit pore water pressure and lower liquefaction risk. Based on the conclusions drawn in previous literature, this paper refines the concept of CS concentration and curing time being the two dominant factors that determine the strengthening effect. The objective of this work is to review CS treatment methodologies and emphasize the critical factors that influence both CS delivery and the ground improving effect. Besides, it also aims to provide references for optimizing the approaches of CS transport and promoting its responsible use in mitigating liquefaction.

Since the concept of sustainable development enjoys popular support in the 21st century, various kinds of unconventional materials were introduced for soil improvement in the past few decades to replace the traditional materials like concrete and lime. This paper compared nanomaterials with other three kinds of representative unconventional materials to demonstrate its superiority in soil treatment. The other three kinds of unconventional materials include microbially induced calcite precipitation (MICP), recycled tire and environmental fiber. Nanomaterial and MICP have a comprehensive effect on soil reinforcement, since they can improve shear strength, adjust permeability, resist liquefaction and purify the environment. Recycled tire and environmental fibers are granular materials that are mostly adopted to reinforce reconstituted soil. The reinforcement mechanisms and effects of these four kinds of unconventional materials are discussed in detail, and their price/performance ratios are calculated to make an evaluation about their market application prospects. It can be seen that nanomaterials have promising prospects. Colloidal silica, bentonite and laponite present a satisfactory effect on liquefaction mitigation for sandy foundation, and carbon nanotube has an aptitude for unconfined compressive strength improvement. Among the investigated nanomaterials, colloidal silica is the closest to scale market application. Despite the advantages of nanomaterials adopted as additives for soil improvement, they are known for unwanted interactions with different biological objects at the cell level. Nevertheless, research on nanomaterials that are adopted for soil improvement are very promising and can intensify the relationship between sustainable development and geotechnical engineering through innovative techniques.