Self-draining string type underreamed anchor supporting structure and construction method

Abstract

The invention discloses a self-draining string type underreamed anchor supporting structure and a construction method. The self-draining string type underreamed anchor supporting structure comprises a self-draining string type underreamed anchor. The self-draining string type underreamed anchor is composed of a variable diameter water filtering steel pipe, a hollow steel pipe, a water absorption expansion ring, a spiral drill tip and a siphon. The forefront end of the self-draining string type underreamed anchor is provided with the spiral drill tip. The spiral drill tip, the variable diameter water filtering steel pipe and the hollow steel pipe are sequentially connected through threads. The water absorption expansion ring is installed on the variable diameter water filtering steel pipe in a sleeving mode. The self-draining string type underreamed anchor is drilled into a foundation pit soil body according to the drilling angle. A lattice frame and a soil retaining plate are arranged on the slope surface of a foundation pit, and the tail end of the self-draining string type underreamed anchor is fixed to the lattice frame. The variable diameter water filtering steel pipe is provided with water filtering holes. A draining channel is provided for foundation soil. The water absorption expansion ring is expanded when meeting water, an expansion section is formed, and the anchoring force is provided. The siphon is inserted into the hollow steel pipe. The initial siphon force is applied to the siphon through a water suction pump, and draining is implemented.

Description

technical field [0001] The invention belongs to the technical field of anchoring engineering, and in particular relates to a deep foundation pit self-draining series-type expansion bolt support structure and a construction method. Background technique [0002] With the rapid development of my country's economy, high-rise buildings and urban underground projects continue to increase, resulting in a large number of deep foundation pit excavation and support projects. With the increase of the scale and depth of foundation pits, engineering accidents and construction problems are gradually increasing, especially in coastal areas of my country, where soft soil strata are widely distributed, with high moisture content and poor physical and mechanical properties, which make the stability and anchorage of deep foundation pits difficult. The contradiction between technologies has become very urgent and prominent. The grouting bolt used in the traditional anchoring technology is diffi...

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Problems solved by technology

[0003] The application number is 201420805558.2, and the patent titled drainage composite self-drilling tire string anchor support structure discloses a combination of drainage measures and expansion head anchoring technology The supporting method is characterized in that the self-drilling tire string anchor is connected by a hollow rod body, a matrix and a drill pipe, and the matrix is ​​expanded to form an enlarged section by inflating the matrix of the self-drilling tire string anchor. Provide higher bearing capacity for the slope surface, rely on anchorage and steel backing plate to fix the self-drilling tire string anchor rod to the grid beam, form a space support structure and anchor the weak soil slope to the stable soil body, through the construction on the slope surface Drainage board is used to achieve the purpose of foundation pit dewatering. This method can effectively drain the water on the slope surface, and the self-drilling tire string anchor has a good anchoring effect, but relatively speaking, the manufacturing process of the self-drilling tire string anchor is relatively difficult. complex, and the drainage board will greatly disturb the slope during construction, which can easily cause the slope soil to collapse. In addition, the drainage and support measures provided by this new type of support are independent of each other, which increases the difficulty of construction with input

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