Split-Lateral Pile Load Test Apparatus for Soil Stiffness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining soil and rock modulus in exploratory boreholes are limited by their small size and minimal displacement, which restricts their ability to assess lateral soil stiffness effectively, especially in deep foundation excavations with larger diameters.
Innovation Solution
A split-lateral test apparatus using hydraulic jacks, such as Osterberg cell (O-Cell) jack assemblies, applies equal and opposite lateral loads to the soil, allowing for direct measurement of soil modulus and generating p-y curves for pile structure design, without requiring an external reaction system or concrete casting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If small-sized devices are used in exploratory boreholes, then the devices can fit into standard boreholes, but the ability to assess lateral soil stiffness is restricted
Solution Approach 1:
The device is divided into multiple functional segments including a frame structure with multiple sensors positioned at different locations and orientations. This segmentation allows the device to measure soil stiffness in multiple directions simultaneously while maintaining a compact size that fits within standard boreholes.
Solution Approach 2:
The invention transitions from single-direction measurements to multi-dimensional measurements by incorporating sensors that measure soil stiffness in multiple directions (radial and tangential components). This dimensional expansion enables comprehensive assessment of lateral soil stiffness despite the device's limited cross-sectional area.
2Length of moving object
If minimal displacement is applied by the device, then the stress field remains small, but the ability to measure soil modulus effectively is limited
Solution Approach 1:
The device performs preliminary measurements at multiple displacement levels, capturing soil response characteristics across a range of stress states. By collecting data progressively from small to larger displacements, the system builds a comprehensive understanding of soil modulus behavior without requiring large single-step displacements.
Solution Approach 2:
The system continuously monitors sensor readings and uses feedback control to adjust applied displacement in real-time. This feedback mechanism enables the device to optimize measurement sensitivity and maintain accurate soil modulus measurements even when operating within minimal displacement constraints.
Data Source
AI summary
Embodiments relate to an apparatus and method for performing a split-lateral load test. Embodiments use a double hydraulic jack to apply two lateral loads, having equal magnitudes and opposite directions, to the soil layer of an excavation for a deep foundation element. Data such as the magnitude of the lateral load and magnitude of the displacement of the loading mechanism upon application of the lateral load can be measured and/or recorded. Embodiments can yield soil modulus (E.sub.s) information in a form analogous to a p-y curve, which can be used to design a pile structure and pile placement, and model a pile response to lateral loading using computer software. Embodiments do not require the casting of concrete, and allow the split lateral loading mechanism to be sequentially positioned, and apply lateral loads, at multiple depths in an excavation. Embodiments simultaneously apply bi-directional lateral loads at multiple depths in an excavation.