Liquefaction susceptibility determination using cone penetration tests

加拿大很容易受到破坏性地震的影响。地震破坏的主要机制之一是土壤液化。当地面震动时，浸透水的松散沙质物质表现得像液体一样。通过识别和稳定松散的砂质土壤，可以减少液化危险和相关的损害。由于获取无粘性砂质或粉质土壤的原状样本困难且费用高昂，工程师依靠现场技术来确定土壤密度，从而确定松散的可液化土壤条件。圆锥贯入试验(CPT)是加拿大最常用的现场测试探头之一，用于表征下垫层土壤，评估其原位密度和液化势。虽然CPT在野外相对容易做，但在解释土壤性质时需要相当小心。目前的认识缺乏对颗粒破碎、土壤矿物学、可压缩性和现场水平应力条件对CPT测量的影响的完全了解。静力触探技术的进展将发展出更可靠的现场土壤状态估计，无论它是否容易液化，并预测更高级的土壤参数。在这项研究合作项目中，将使用韦斯特的微型圆锥贯入试验来开发一种用于估计无粘性土的现场液化敏感性的改进方法。研究了细粒含量、砂岩矿物学和水平应力对砂岩稳定性的影响。这项研究所产生的更准确的CPT测试和解释将显著提高目前在实际情况下推断土壤密度的精度，从而使加拿大涉及CPT的岩土勘察和设计更加准确和可靠。有了更好的理解，就可以避免在这些潜在的可液化土壤上施工，或者可以采用改进的土壤加固技术来减少液化破坏。

Canada is vulnerable to destructive earthquakes. One of the leading mechanisms of earthquake damage is by soil liquefaction. When the ground shakes, loose sandy materials saturated with water behave like a liquid. Liquefaction hazard and the associated damage can be reduced by identifying and stabilizing loose sandy soils. Because of the difficulty and large expenses in obtaining undisturbed samples of cohesionless sandy or silty soils, engineers rely on in-situ field techniques to determine soil density and thus loose liquefiable soil conditions. Cone penetration testing (CPT) is one of the most commonly used field testing probes in Canada to characterize the underlying soil, evaluate its in-situ density, and liquefaction potential. Although CPT is relatively easy to do in the field, it requires considerable care for interpreting soil properties. The current state of knowledge is lacking complete understanding of the effects of particle crushing, soil mineralogy, compressibility and in-situ horizontal stress conditions on CPT measurement. Advances in CPT will develop more reliable estimates of in-situ soil state, whether it is susceptible to liquefaction or not, and predicting more advanced soil parameters. In this research collaboration project, Western's miniature cone penetration test will be used to develop an enhanced method for estimating in-situ liquefaction susceptibility of cohesionless soils. The effects of fines content, sand mineralogy and horizontal stress will be also studied. More accurate CPT testing and interpretation resulting from this research will markedly improve the current precision in inferring soil density in practical situations, and thus more accurate and reliable geotechnical investigation and design involving CPT in Canada. With an improved understanding, construction could be avoided on these potentially liquefiable soils or improved soil strengthening techniques could be employed for reducing liquefaction damage.