Study On Reinforcement Schemes And Corresponding Effects Of Jet Grouting Pile Ground

Jet grouting pile is a soil-cement pile set in soft soil ground, and composes jet grouting pile composite foundation with soil around piles. It adopts high pressure jet grouting technique and has certain superiorities, i.e. compact combination of piles and soil, flexible pile shape, simple construction equipments and fewer environmental impacts, thus it is especially suitable for ground reinforcement after project completed, and has been diffusely applied. Nevertheless, the theoretic development of jet grouting pile lags behind the engineering practices, and the conservativeness on design always causes certain waste. This paper assessed a strengthening governance item of unequal settlement of ground from a certain project in northern Shanxi, the ANSYS software was used as research tool, and three parameters:the length (L), diameter (D) and spacing (S) of pile was selected to evaluate the ground reinforcement effect of jet grouting pile, each of the parameters possessed five different schemes to make comparisons. At the same time, each parameter was further subdivided into three parts:total settlement, horizontal deformation and stress distribution, to study minutely. Research results are listed as follows:1) Calculation of bearing capacity. Common used area ratio method and stress ratio method were compared and analyzed, the results showed that area ratio method was recommended for the design of jet grouting piles. Besides, a calculation method of area of replacement rate suitable for jet grouting piles underpinning project was put forward.2) Calculation of settlement in reinforced area. Composite compression modulus Esp is a key parameter of common used composite modulus method, a formula of composite compression modulus Esp considering efficiency factor of bearing capacity of pile and soil was constructed.3) The circular pile used in practical engineering is often replaced by uniform section square pile in jet grouting pile composite foundation finite element model, which simplifies model, but it produces relatively larger error at the same time. In this paper, the model was constructed by circular pile and divided into four layers of soil according to practical project, and all partitioned via hexahedral mesh.4) In view of engineering instance, jet grouting pile foundation reinforcement schemes with different pile length (L), pile diameter (D), pile spacing (S) were constructed and calculated, the results were analyzed and summarized. In addition, five optimized principles for jet grouting pile reinforcement scheme were put forward.5) Optimal design of jet grouting pile reinforcement scheme was made according to optimized principles, the pile length reduced zero point five meter, the pile spacing was reasonably adjusted, good reinforcement effect and economic benefit was obtained.