US sending several thousand troops to the border to install concertina wire barriers

AP:

The U.S. will be sending “several thousand” more American troops to the southern border to provide additional support to Homeland Security, Acting Defense Secretary Pat Shanahan said Tuesday, providing for the first time new estimates for the next phase of the military aid.

He said the troops will mainly be used to install additional wire barriers and provide a large new system of mobile surveillance and monitoring of the border area. Plans call for about 150 more miles of concertina wire placed mainly in the gaps between ports of entry.
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Officials said that the majority of the troops going to the border now will be combat engineers and support forces who will install the additional barriers. The expectation is that they will complete the job in a few months and then be able to go home.

Many of the others will start the expanded surveillance mission which will last at least through September. The U.S. forces will use Customs and Border Protection vehicles that have mounted surveillance cameras and they will monitor the border.
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The concertina makes it difficult to breach a defended area.  Those who try to breach it can usually be detected and dealt with before they can cut their way through the wire.  In a military operation against this kind of barrier it usually requires Bangalore torpedoes which are the equivalent of a long pipe loaded with explosives to blow a breach, the infantry can attack through.  It is unlikely the migrants would have access to such breaching tools.