Centrifuge Modelling of Compaction Grouting

9622399压实注浆是在高压下将刚性水泥基浆液注入土体。现有的和明确的证据表明，该技术可以作为一种方法来阻止或扭转地面沉降的影响，并改变和改善现有土壤的特征和原位应力条件。这项工程绝大多数是由专业顾问和承包商来完成的，但即使是在他们中间，对土壤和灌浆力学的细节仍然存在疑问。该项目将回答有关注入深度、灌浆压力、灌浆混合物、土壤条件和原位应力之间相互关系的问题，以及由此产生的对土壤压实、剪切变形和土壤位移的影响。初步的离心机试验表明，这种小的，1-g模型的测试技术可以证明一般的行为机制。然而，应力正确的离心机模型是必要的，以建立可靠的全尺寸现场响应表示。在这项工作中，有一项承诺是与正在进行的由美国国家科学基金会赞助的FEM建模研究和北卡罗莱纳州立大学注浆的全尺寸现场测试以及美国陆军部队水道实验站进行合作互动。为该合同完成的离心机模型将非常有助于解决与注浆和注入方案设计相关的问题，包括注入深度、压力、注浆角度和表面附加物等可变参数。灌浆承包商也承诺为该项目提供建议，并计划对研究人员团队进行实际培训。＊＊＊

9622399 Compaction grouting is the injection under high pressure of stiff cement-based grout into soil. There is existing and clear evidence that the technique works as a method to halt or reverse the effects of ground settlement, and to modify and improve characteristics of existing soils and in situ stress conditions. The application is overwhelmingly in the hands of specialized consultants and contractors, but even among them, questions persist about the details of soil and grout mechanics. This project will answer questions on the interrelationship between injection depth, grout pressure, grout mix, soil conditions and in situ stress, and the resulting effects on soil compaction, shear deformation, and soil displacement. Preliminary centrifuge indicates that this test technique with small, 1-g models can demonstrate general mechanisms of behavior. However, stress-correct centrifuge models are necessary to develop reliable representation of full-scale field response. There is a commitment in this work for cooperative interaction with on- going NSF-sponsored research on FEM modeling and full-scale field testing of grout injection at North Carolina State University, and with the U.S. Army Corps' Waterways Experiment Station. The centrifuge models completed for this award will be highly complimentary to address questions relating to the design of grout and injection schemes, including variable parameters such as injection depth, pressure, grout injection angle, and surface surcharge. Commitment has also been made by grouting contractors to advise on this project, and plans are included for practical training of researcher teams. ***