Liquefaction susceptibility determination using cone penetration tests

加拿大易受破坏性地震的影响。地震破坏的主要机制之一是土壤液化。当地面震动时，松散的桑迪物质被水饱和，表现得像液体。通过识别和稳定松散的桑迪，可以减少液化危害和相关损害。由于难以获得无粘性桑迪或粉土的原状样品且费用高昂，工程师们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。静力触探（CPT）是加拿大最常用的现场测试探头之一，用于表征下伏土壤，评估其原位密度和液化潜力。虽然CPT在野外相对容易进行，但在解释土壤性质时需要相当小心。目前的知识状态是缺乏完整的了解颗粒破碎，土壤矿物学，压缩性和原位水平应力条件对CPT测量的影响。CPT的进步将开发更可靠的估计原位土壤状态，无论是易液化与否，并预测更先进的土壤参数。在这项研究合作项目中，西方的微型圆锥贯入试验将被用来开发一种增强的方法，估计在现场的无粘性土壤的液化敏感性。还将研究细粒含量、砂矿物学和水平应力的影响。通过本研究，可以得到更准确的静力触探试验结果，并对试验结果进行解释，这将显著提高目前在实际情况下推断土壤密度的精度，从而使加拿大的静力触探岩土工程勘察和设计更加准确可靠。随着认识的提高，可以避免在这些潜在的液化土壤上进行施工，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.