Mud balance system and control method based on the height difference measuring instrument inside and outside the borehole

Abstract

The invention discloses a mud balancing system based on measuring instruments for height difference of water levels inside and outside a drilling hole and a control method. The system comprises a measurement device and a mud circulating device, wherein the mud circulating device comprises a mud storage tank and a pump; the measurement device comprises a connecting wing plate connected with a retaining cylinder for drilling, one sleeve is arranged on each of the inner side and the outer side of the connecting wing plate, a laser range finder is arranged at the upper part of each sleeve, a laserreflecting plate is gliding matched in each sleeve, each laser reflecting plate is connected with one floating ball through a hard floating rod, and each floating rod is glidingly matched in a central hole in a bottom plate of each sleeve; the mud circulating device also comprises a first three-way solenoid valve and a second three-way solenoid valve. The method is characterized in that a main controller switches the mud replenishing state and the mud pumping state according to the height difference of water levels inside and outside the hole. According to the system and the method, mountingis convenient, the measurement process is convenient, labor is saved, and the measurement result is accurate.

Description

technical field [0001] The invention relates to the field of bored piles in pile foundation construction, in particular to a mud balance system and a control method based on a height difference measuring instrument between the mud liquid level in the borehole and the water level outside the hole. Background technique [0002] Large-diameter bored piles are widely used in foundation projects such as large bridges, railways, liquefied natural gas and super high-rise buildings. In the process of drilling, mud is used to maintain the pressure balance inside and outside the borehole. When the mud circulates, the pressure difference between the mud and groundwater or the sea surface or river surface outside the hole is used to make the mud form a mud skin on the hole wall, realize the hole wall reinforcement to prevent collapse, and stabilize the water level in the borehole. The pressure difference inside and outside the hole is realized by the height difference between the mud s...

AI Technical Summary

Problems solved by technology

However, there are still deficiencies in the above method: the main reason is that this method has high requirements on the working site environment, and the working environment of bored piles is harsh. During the reverse circulation process, the backflow mud impacts the mud liquid surface, resulting in a large number of mud particles and impurities in the air, which have a negative effect on the propagation of ultrasonic waves. Causes interference and reduces measurement accuracy

There is also the application of CN207019744U, which proposes that a force transmission device and a detection device are arranged on the outer wall of the mixing tank, and the pressure signal is transmitted by the force transmission device, and is converted into liquid level information by the detection device. The weak point of this scheme is: mud It is difficult to find a space to install the force transmission device and detection device in the casing, and the inside and outside of the casing are filled with mud, which constantly rubs against the force transmission device and detection device, which is very easy to damage it, and the pressure information is converted into liquid level information A complete set of corresponding programs and information processing equipment is required, which makes the whole device complex and inconvenient to assemble

The defect of this circulation system is: the degree of automation is low, each adjustment requires workers to manually control the two pumps according to the measurement results to achieve slurry replenishment or pumping, and in order to ensure pressure balance, the frequency of adjustment is high. Manpower consumption is large; moreover, the system requires two pumps to achieve adjustment, which increases the cost and cost

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