Study On Mechanical Properties Of The Reinforced Cement-soil Anchor By Jet Grouting

The rock and soil medium, which is the research object of geotechnical engineering, is characterized as uncertainty, empiricism and locality. Different rock and soil mass from different regions have experienced different geological process, thus, they have very different engineering properties. Because of this distinction, the diversity of the technologies which meet the requirements of different engineering is needed to make sure that programs and technologies are suitable for the local conditions. As an economical and effective method of geotechnical reinforcement and structural stabilization, ground anchorage is widely applied to the engineering of slope stabilization, foundation ditch, tunnel and anti-float. Based on the original anchoring technologies, new anchoring technologies are developed to meet the local conditions. Among them, the reinforced cement-soil anchor by jet grouting is one that combines the high pressure jet grouting technique and common anchor, with better applicability than the common anchor in the projects of soft soils and the projects that require higher anchoring force per unit length. This research aims at analyzing and studying the application of this anchor in engineering. Its contents and findings are as follows.Firstly, it introduces the technological principles, construction technologies and characteristics of the reinforced cement-soil anchor by jet grouting, then analyzes the similarities and differences with the common anchor. It proposes the lateral resistance softening load transfer model referring to the head-expansion. After verifying its rationality, we then based on this model to analyze the effects of the diameter of anchorage, modulus of elasticity, extended head parameter and limit friction stress on its load transfer mechanism and bearing capacity.Secondly, through the construction of finite element model, it simulates the carrying force mechanism of reinforced cement-soil anchor by jet grouting resulted from the pullout capacity. It also explores the effects of the design parameters--non extended segment and bulb size on its load transfer and pullout resistance. Then, it provides advice for the reasonable value range of these parameters.Lastly, it states the load transfer mechanism of the reinforced cement-soil anchor by jet grouting with the expanded head and its failure types in different soil layers and deduces the computation of the ultimate pullout capacity on the occasion of overlaying soft layers. Summaries of the current load calculating methods of the bit expanded anchor and their similarities and differences by comparing with the results of examples are provided.