Subsoil strengthening by using jet-grouting technology

摘要

The weak subsoil conditions like an anthropogenic, organic and cohesive soil, contribute to the application of subsoil strengthening. One of the most popular technology of subsoil strengthening is jet-grouting. Jet-grouting process consists in high-pressure injection of an inject (the cement grout usually) stream to the soil massif. The stream cuts and crushes the soil structure. Performance is started by an insert of drilling rods with high-pressure nozzle at the end, in a subsoil at expected depths. During pulling the rod, the inject is flowing from the nozzle under a high pressure. Soil and cement particles fill space in the range of erosion stream, creating the binding rigid block, called soilcrete. The blocks may be shaped into eg. columns. The main motivation of my research project is preparing the explanation of interaction between jet-grouting columns and subsoil. It can be useful for designers to optimizing the procedure of dimensioning columns. The key goal is preparing the numerical model, which can be useful to illustrate the real conditions of subsoil strengthening by using jet-grouting columns. The computational model describes the interaction between group of jet-grouting columns and soil. Presented model will reflect the essence of jet-grouting technology, and after checking the results with in situ tests it will be also used to verify engineering methods of dimensioning columns. The main element of this analysis is selection and calibration of computational model of the "group of jet-grouting columns - subsoil" interaction. The starting point for creating a model is the concept of dividing the model into three zones: jet-grouting columns, subsoil and the contact layer, formed between the columns and the soil massif.