Strengthening Mechanism Of MJS And RJP High Pressure Rotary Jet Grouting Pile And The Quality Of Pile Forming

With the rapid development of China’s urbanization and industrialization in, a growing number of cities, villages and industrial parks are unavoidable to construct buildings on soft soil foundation. Then the reinforcement of soft soil foundation is needed. At the same time underground space development has become an important theme in China’s first-tier cities. Therefore, deep foundation pit supporting is becoming increasingly common, and the structure of deep foundation pit supporting more and more complicated. Based on the above background, the high-pressure jet grouting pile this paper will research is proposed.This thesis chose the deep foundation pit supporting engineering of No.55 plot on Haimen Road as research background and introduced MJS and RJP these two methods of the high pressure jet grouting pile. The constructive mechanism and construction technology of MJS and RJP were researched through real-time monitoring, theoretic analysis and numerical simulation. In the meantime, the author carried out the construction monitoring and numerical simulation of ABAQUS on the test pile of these two kinds of high pressure jet grouting pile. Finally, the methods of quality detection and arrangement of piles were referred to. The main research contents are as follows: Research the basic forms of high pressure jetting flow and introduce single-pipe jetting flow, double-pipe jetting flow, triple-pipe jetting flow, and multi-pipe jetting flow; Research the forming mechanism of the high-pressure jet grouting pile; Introduce the construction process of MJS and RJP these two methods of the high pressure jet grouting pile in detail; Conduct the completed construction monitoring of MJS and RJP these two methods of the high pressure jet grouting pile and get some important monitoring data including soil deviation, pore water pressure, layer settlements. Then compare the collected data and find out the settlement of the high pressure jet grouting pile using MJS and RJP is not big, nor is the change of pore water pressure; In order to obtain the high-pressure jet grouting pile’s stress and distortion situation during the excavation of deep foundation pit, this paper chooses a section of the pile body and uses the software ABAQUS to conduct simulation calculation on pile’s stress and distortion situation. Along with the excavation of deep foundation pit, the distortion law of high-pressure jet grouting pile can be summarized. The simulated result was compared to the data of site real-time monitoring.After analyzing the result of this comparison, the following conclusions were drawn:The improved high-pressure jet grouting pile, that is, MJS and RJP construction methods. Their construction technology are more simple and low-cost. MJS and RJP construction methods have strong applicability with high benefit; Because the foundation strengthened by the high-pressure jet grouting pile has small settlement, this construction technology can be used to protect important buildings; Super-deep and super-large foundation pits supporting has always been a difficult problem. Applying MJS and RJP construction technology to deep and large foundation pits supporting provides a good solution for the problem; After the construction of the high-pressure jet grouting pile, pore water pressure is small out of monitoring results. MJS and RJP construction technology can be applied to the construction of water sealing curtain.