بررسی عددی روش های مختلف برجا در تخمین باربری شمع

نوع مقاله : مقاله کامل پژوهشی

نویسندگان

1 دانشکده فنی، گروه مهندسی عمران، عضو پژوهشکده علوم و فن آوری‌های نوین، دانشگاه شاهد

2 دانشکده مهندسی عمران، دانشگاه تهران

چکیده

با توجه به عدم اطمینان نتایج روابط متداول محاسبه ظرفیت باربری شمع ­ها، نیاز به انجام آزمایش های برجا محسوس است. هدف تحقیق ارائه شده در این مقاله مقایسه تئوریک آزمایش های برجای تعیین باربری شمع ­ها، به­ خصوص سه روش بارگذاری استاتیکی شمع، استفاده از روابط دینامیکی کوبش شمع (Dynamic Pile Driving Formula) و استفاده از روابط مبتنی بر تئوری موج تنشی میباشد. در این مقاله به ­کمک مدل­سازی عددی کوبش شمع و آزمایش بارگذاری استاتیکی شمع، نتایج به­ دست آمده از هر یک از سه روش فوق با هم و با نتایج حاصل از روابط متداول محاسبه ظرفیت باربری مقایسه شده است. در روش استفاده از روابط دینامیکی، از رابطه هیلی (Hiley) که تنها رابطه است که بر اساس مقدار فرورفت و برجهندگی سر شمع باربری را تخمین می­زند، استفاده شده است. نتایج مقاله حاکی از آن است که روند تغییرات باربری در رابطه هیلی اصلاح شده و روش مبتنی بر تئوری موج، تطابق خوبی با سایر روش­ ها از جمله بارگذاری استاتیکی و روابط کلاسیک طراحی دارد. همچنین باربری به­ دست آمده از این دو روش، به­ دلیل ماهیت دینامیکی آن­ها، از جواب سایر روش ­ها بزرگ­تر است.

کلیدواژه‌ها

عنوان مقاله [English]

Numerical Study of In- Site Tests for Pile Capacity Estimation

نویسندگان [English]

  • Mahdi Rojhani 1
  • Ali Fakher 2
1 School of Civil Engineering, member of Institute of Modern Sciences and Technologies, Shahed University, Tehran, Iran
2 School of Civil Engineering, University of Tehran, Tehran, Iran
چکیده [English]

Pile capacity estimation by conventional design equations is not so accurate. Beside of uncertainty of geotechnical parameters and the defect of design equations, during pile installation, soil is highly disturbed. In pile foundation projects, it is necessary to confirm pile capacity by in-situ tests. Many methods proposed to perform in-situ such as static pile loading test, pile driving formulas based on penetration and rebound of pile during driving and wave equation method. Among these methods, the use of pile driving formula is the easiest and the most economical method. Hiley formula is the only pile driving formula that uses pile rebound in combination with pile penetration for pile capacity estimation. Static pile loading is the most accurate and also expensive test. Evaluation of capacity by wave equation method is newer than static loading and Hiley formula and with moderate accuracy and cost. In this research, by numerical simulating of pile driving and pile loading, the results of the mentioned methods (Hiley formula, Wave equation, pile loading test) will be compared.
.

In this paper, Hiley formula has been evaluated using numerical simulation of pile driving and variation of penetration and rebound of pile. Then, the pile capacity estimation using Hiley equation based on penetration and rebound of pile obtained from numerical simulation. The pile capacity has also been calculated by Case method using force and velocity of pile head obtained from numerical simulation. In addition to numerical simulation of pile driving, static pile loading test has been numerically simulated and its results have been used in estimation of pile capacity.

According to these results, the trend of capacity variation in static pile loading, modified Hiley formula and Case methods are all, to some extent, in good agreement with the results of design equations. However, capacity values obtained from Hiley formula and Case method are, almost in all cases, higher than capacity by static loading test and design equation.

کلیدواژه‌ها [English]

  • In-site pile tests
  • Pile capacity
  • Hiley formula
  • Wave equation
  • Pile loading

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نشریه مهندسی عمران و محیط زیست دانشگاه تبریز
دوره 52.1، شماره 106 - شماره پیاپی 106
بهار 1401
خرداد 1401
صفحه 81-92

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