| Friction pile is an effective means of supporting which is widely used in slope, landslide control project. Relied on the research project "Longmen seismic belt damaged slide slope damage prevention project health assessment and remediation key technologies", friction pile health diagnostic index system and evaluation system can be studied through data collection, site survey, physical simulation test, numerical simulation and pile testing. From them, a few conclusions can be made.(1)According to the site investigation, the common failure types of friction pile can be divided into3types.①Sliding Engineering anchoring section and deformable body damage. It includes roof damage, failure of soil arching.②Anti-slide pile body damage. It includes toppling failure, shearing failure and flexural failure.③damage caused by design and construction of the destruction. It includes pile necking, segregation, concrete crack, etc.(2)Three groups of physical simulation tests are designed to simulate deformations of friction pile slip, flexural, shear and other failure modes. Based on analysis of friction pile’s displacement, inclination, pile stress, soil pressure and other data, friction pile’s top displacement and angle indicator system can be got to divide injuries piles into4grades.(3) Study on existing pile testing methods and then select the suitable piles site testing approach. Through theories and extensive filed testing engineering examples, pile integrity assessment standards can be developed which divide the health condition into4levels. Class I pile, pile overall integrity, do not do any processing. Class II pile, a slight defect pile can be handle with clearing the surface dirt, good drainage dredging process and necessary patches. Class III pile, pile with obvious defects includes cracks piles and piles off. It must be done with some measures such as drainage, anchoring reinforcement, testing on the pile integrity and drill core samples taken from. Based on the consolidated results, the necessary measures are taken to reinforce. Class Ⅳ pile, the pile is seriously flawed, including cracks and broken piles. Drill core sample testing is used to confirm the repair or scrap, and re-survey, design and construct.(4)Combined with pile displacement indicators, pile inclination indicator, anchoring section and deformable body indicators, NDT pile integrity indicators and corresponding specification, the friction pile’s health diagnosis evaluation system can be made and be divided into4grades. It concludes piles assessment’s evaluation content, evaluation process, evaluation index and the corresponding disposal measures.(5)The diagnosis of Anti-slide pile health should be based on the principle of convenient, simple, practical,and it is better to make evaluation index easy to access and also make it the key factors of the judgment of anti-slide health condition, the specific work mainly includes field investigation, deformation measurement, nondestructive testing, pile more verification, make the conclusion. Specific include:A. scene investigation mainly includes survey on the soil proterty of slope, drilling should be carried out on the slope if it allowed, confirm the intensity of soil, anchor solid strength and so on, and find out the anchoring segment and the deformation of the landslide combined with the deformation of slope body signs. B. Do some field measurement, including top displacement of anti-slide pile and the dip Angle indicators and evaluate damage anti-slide pile. C. Test every function of the slide-resistant pile by pile nondestructive testing means of the anti-slide pil and to take corresponding measures according to test results. D. in order to get the most intuitive and reliable results,drilling and sample if it damage more serious or uncertainty evaluated or identified as III pile during the test. E. after a series of corresponding detations for anti-slide,make out the test results and disposal plan.(6)By means of finite element numerical simulation flac3D against sliding piles health diagnostic indicator system fitting analysis, dynamic analysis using strength reduction studied natural conditions, which studied the slope safety issues with different damaging degree under natural conditions and earthquake conditions. The result shows:slope safety factor without slide-resistant pile under natural conditions is1.17; slope safety factor without slide-resistant pile under earthquake conditions is0.8; slope safety factor with slide-resistant pile under earthquake conditions is1.3; The entire support engineering was intact, which the pile can be determined as the class I. The slope safety factor of slide-resistant pile damaged to25%under earthquake conditions is1.2, there appeared to have roof damage and soil arching effect failures, slide-resistant pile is determined as the class II. The slope safety factor of slide-resistant pile damaged within50%under earthquake conditions is0.95, the slide-resistant system was seriously damaged which determined the pile as class Ⅲ. When the pile damaged greater than50%, the slope safety factor tends to Fos=0.8like without slide-resistant pile, the pile was mostly damaged, determined as Class Ⅳ. |
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