Research On Rectification And Reinforcement Technology About A Semi-detached Villa In Chengde

The tilting of buildings has been bothering people’s production and life. Furthermore, some buildings have to be erected on the rough ground nowadays due to the increasing scale of urban construction. Therefore, engineering accidents such as the uneven settlement and tilting might happen because of the careless management during the investigation, design, construction and monitoring. By2030, there will be a sharp decrease in the new construction in China while the construction renovation and disease management projects, among which the rectification is an important branch, will account for a high share of the building field. The rectification and reinforcement cost much less than the new construction and avoid the malpractices in the demolition work simultaneously. In addition, the rectification and reinforcement technologies make it possible to protect a large number of endangered cultural relics which face the problem of tilting, structural damage and deterioration. However, the rectification project is in need of the firsthand resources of design, construction and monitoring as well as the fully worked-out theories, so the research on the rectification technology bears a great significance.Based on the rectification and reinforcement project of a semi-detached villa in Chengde, the thesis first reviews the history of building rectification and reinforcement, the causes for tilting and the relevant technologies. In the next place, a detailed analysis of the causes for tilting of the semi-detached villa is made and it is attributed to the irregular foundation, green belt sprinkling and the infiltration of surface water. Then according to the characteristics of the villa, a radial-foundation horizontal digging and a pit-jacked pile, the two reinforcement programs are designed, based on which the rectification goals are decided, such as the amount of rectification, the range and parameter of the soil excavation as well as the parameter of pit-jacked pile execution. Finally, the slope returned from13.1‰o to2.0‰through the practice of the rectification and reinforcement which lasted for82days, grounded on which some conclusions are drawn as follows:(1). In terms of the low and middle buildings with many posts outside, it is feasible, controllable and precise to carry out the rectification and reinforcement through the combination of radial-foundation horizontal digging, digging under the posts, pit-jacked pile and the double liquid grouting. (2). It is convenient and effective to reinforce the ground by the way of double liquid grouting in order to avoid the seesaw effect during, the rectification.(3). Many posts are preferred out of the low and middle villa for beauty. Therefore, the specific measures are necessary to ensure the agreement between the rectification of villas and that of the posts outside.(4). When reinforcement is conducted through pit-jacked piles, the digging on the more-subsided part should be started after there is a certain amount of settlement on the less-subsided part and the center of the gravity of buildings is rectified.(5). In terms of the rectification of two-way tilting, the secondary deviation should be adjusted to the expectations before the rectification of the primary tilting.The technologies adopted in the rectification and reinforcement of the semi-detached villa carry significant implications for the similar projects in the other low and middle buildings with many posts outside.